Systems, devices, and methods for authentication in an analyte monitoring environment

ABSTRACT

Systems, devices, and methods are provided that allow the authentication of devices within analyte monitoring systems. The analyte monitoring systems can be in vivo systems and can include a sensor control device with a sensor and accompanying circuitry, as well as a reader device for communicating with the sensor control device. The analyte monitoring systems can interface with a trusted computer system located at a remote site. Numerous techniques of authentication are disclosed that can enable the detection of counterfeit components, such as a counterfeit sensor control device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional applicationSer. No. 15/367,922, filed Dec. 2, 2016, which is a divisional of U.S.Non-Provisional application Ser. No. 14/574,017, filed Dec. 17, 2014,now U.S. Pat. No. 9,544,313, which claims priority to U.S. ProvisionalApplication No. 61/921,372, filed Dec. 27, 2013, all of which areincorporated by reference herein in their entireties for all purposes.

FIELD

The subject matter described herein relates to systems, devices, andmethods for authentication in an analyte monitoring environment.

BACKGROUND

The detection and/or monitoring of analyte levels, such as glucose,ketones, lactate, oxygen, hemoglobin A1C, or the like, can be vitallyimportant to the health of an individual having diabetes. Diabeticsgenerally monitor their glucose levels to ensure that they are beingmaintained within a clinically safe range, and may also use thisinformation to determine if and/or when insulin is needed to reduceglucose levels in their bodies or when additional glucose is needed toraise the level of glucose in their bodies.

Growing clinical data demonstrates a strong correlation between thefrequency of glucose monitoring and glycemic control. Despite suchcorrelation, many individuals diagnosed with a diabetic condition do notmonitor their glucose levels as frequently as they should due to acombination of factors including convenience, testing discretion, painassociated with glucose testing, and cost. For these and other reasons,needs exist for improved analyte monitoring systems, devices, andmethods.

SUMMARY

A number of systems have been developed for the automatic monitoring ofthe analyte(s), like glucose, in bodily fluid such as in the bloodstream, in interstitial fluid (“ISF”), dermal fluid, or in otherbiological fluid. Some of these systems are configured so that at leasta portion of a sensor control device is positioned below a skin surfaceof a user, e.g., in a blood vessel or in the subcutaneous tissue of auser, so that the monitoring is accomplished in vivo. As such, thesesystems can be referred to as “in vivo” monitoring systems. In vivoanalyte monitoring systems include “Continuous Analyte Monitoring”systems (or “Continuous Glucose Monitoring” systems) that can broadcastdata from a sensor control device to a reader device continuouslywithout prompting, e.g., automatically according to a broadcastschedule. In vivo analyte monitoring systems also include “Flash AnalyteMonitoring” systems (or “Flash Glucose Monitoring” systems or simply“Flash” systems) that can transfer data from a sensor control device inresponse to a scan or request for data by a reader device, such as witha Near Field Communication (NFC) or Radio Frequency Identification(RFID) protocol. In vivo analyte monitoring systems can also operatewithout the need for finger stick calibration.

The in vivo analyte monitoring systems can be differentiated from “invitro” systems that contact a biological sample outside of the body (orrather “ex vivo”) and that typically include a meter device that has aport for receiving an analyte test strip carrying bodily fluid of theuser, which can be analyzed to determine the user's blood sugar level.

In vivo monitoring systems can include a sensor that, while positionedin vivo, makes contact with the bodily fluid of the user and senses theanalyte levels contained therein. The sensor can be part of the sensorcontrol device that resides on the body of the user and contains theelectronics and power supply that enable and control the analytesensing. The sensor control device, and variations thereof, can also bereferred to as a “sensor control unit,” an “on-body electronics” deviceor unit, an “on-body” device or unit, or a “sensor data communication”device or unit, to name a few.

In vivo monitoring systems can also include a device that receivessensed analyte data from the sensor control device and processes and/ordisplays that sensed analyte data, in any number of forms, to the user.This device, and variations thereof, can be referred to as a “readerdevice” (or simply a “reader”), “handheld electronics” (or a handheld),a “portable data processing” device or unit, a “data receiver,” a“receiver” device or unit (or simply a receiver), or a “remote” deviceor unit, to name a few. Other devices such as personal computers havealso been utilized with or incorporated into in vivo and in vitromonitoring systems.

An in vivo system manufacturer can provide users with both the sensorcontrol device and the corresponding reader device; in some cases thetwo can be sold as a set. The sensor control device can have a limitedlifespan and can be replaced periodically (e.g., every two weeks), butthe reader device can be used for a significantly longer period of timeand is reusable with each new replacement sensor control device. Inthose cases the manufacturer typically sells sensor control devicesindividually to the user.

For competitive, quality, and other reasons, manufacturers generallywant users to operate only those sensor control devices made or suppliedby that manufacturer, with reader devices also made or supplied by thatmanufacturer (or reader devices using software supplied by thatmanufacturer). Similarly, manufacturers may want to restrict the use ofcertain models of sensor control devices with certain readers, and maywant to restrict the use of sensor control devices and/or readers toonly certain geographic regions. Therefore, a need exists to ensure thatsensor control devices supplied by a manufacturer are used only withthose reader devices either supplied by that manufacturer or operatingwith software supplied by that manufacturer, and vice versa.

Furthermore, in recent years the threat of counterfeiting has become agreater concern. Manufacturers have a need to guard against thepossibility of a third party selling “look-alike” sensor control devicesthat are designed for use with the manufacturer's reader device, or adevice operating with software provided by the manufacturer, but are notin fact designed and built by the manufacturer.

A number of embodiments of systems, devices, and methods are providedthat allow for the authentication of components within an in vivo or invitro analyte monitoring environment. These embodiments can allow forthe detection of unauthorized devices, or devices supplied by othermanufacturers, as well as to restrict the types of devices, regardlessof manufacturer, that are used within the environment. It should benoted that all embodiments described herein are for example only and arenot intended to further limit the scope of the subject matter claimedherein beyond the explicit language of the claims themselves.

Although the analyte monitoring systems, devices, and methods can be forin vivo use, in vitro use, or both, the majority of the exampleembodiments will be described as operating within an in vivo analytemonitoring system.

For example, embodiments of methods of authentication in an in vivoanalyte monitoring system can include receiving, by a reader device, anidentifier from a sensor control device over a local wirelesscommunication path, where the sensor control device includes a sensorand analyte monitoring circuitry, and the sensor is adapted to beinserted into a body of a user, sending the identifier from the readerdevice over an internet to a trusted computer system having a storedregistration database, and receiving, by the reader device, anauthentication result from the trusted computer system over theinternet, where the authentication result indicates whether the sensorcontrol device is or is not authorized to operate with the readerdevice.

In many embodiments described herein, the identifier can be a serialnumber of the sensor control device, a random number, one or morecalibration parameters for the sensor control device, other values, andany combinations thereof.

In these and other embodiments, the methods can further include sendingan identification request from the reader device over the local wirelesscommunication path to the sensor control device, where the sensorcontrol device sends the identifier to the reader device in response toreceipt of the identification request. The methods can also includedetermining, by the trusted computer system, authenticity of theidentifier by reference to a stored registration database. If theidentifier is in the stored registration database, the methods caninclude determining if the identifier is associated with an unuseddevice.

In some embodiments, the registration database can include one or morecompilations of used and unused identifiers, and the methods can includeupdating the registration database by associating the identifier with aused device. In some embodiments, the authentication result authorizesthe reader device to operate with the sensor control device if theidentifier is associated with an unused device, and the authenticationresult does not authorize the reader device to operate (or prevents itfrom operating) with the sensor control device if the identifier isassociated with a device that has already been used or is counterfeit.

A number of communication protocols can be used with the embodimentsdescribed herein. For example, the reader device can communicate withthe sensor control device over a local wired or wireless communicationlink. Wireless protocols that can be used include Wi-Fi, near fieldcommunication (NFC), radio frequency identification (RFID), Bluetooth,or Bluetooth Low Energy, to name a few.

A number of types of reader devices can be used with the embodimentsdescribed herein. For example, the reader device can be a smart phone, atablet, a wearable electronic assembly such as a smart watch or smartglasses, or the like. The reader device can include location determininghardware capable of determining a current location of the reader device,such as global positioning system (GPS) hardware.

In embodiments having location determining hardware, the methods caninclude sending the current location of the reader device over theinternet to a trusted computer system, which can generate anauthentication result that either authorizes or does not authorize thereader device to operate with the sensor control device based on thecurrent location. In some embodiments the methods can include, if theidentifier is not authorized for use in the current location, displayinga message on a display of the reader device indicating that the sensorcontrol device is not authorized for use in the current location.

The methods can further include reading, with the reader device if anauthentication result permits operation of the reader device with thesensor control device and if the sensor has been inserted into the bodyof the user, information indicative of an analyte level of the user fromthe sensor control device and displaying the analyte level on a displayof the reader device.

Other example embodiments are also described of in vivo analytemonitoring systems having a reader device. The reader device can includea first receiver capable of receiving an identifier and sensed analytedata from an in vivo sensor control device over the local wirelesscommunication path, communication circuitry capable of transmitting theidentifier over the internet to a trusted computer system, a secondreceiver capable of receiving an authentication result over the internetfrom the trusted computer system, and a processor programmed to read theauthentication result and, if the authentication result indicates thatthe sensor control device is authentic, cause the sensed analyte data tobe displayed to the user. If the authentication result indicates thatthe sensor control device is not authentic, then the processor can beprogrammed to cease operation of the reader device with the sensorcontrol device. In some embodiments, the processor is further programmedto generate an identification request for transmittal by the readerdevice over the local wireless communication path to the sensor controldevice.

The system can further include the sensor control device that, in someembodiments, can include a sensor adapted to be inserted into a body ofa user, analyte monitoring circuitry coupled with the sensor, a memorycapable of storing an identifier, and communication circuitry capable ofcommunicating the identifier and sensed analyte data over a localwireless communication path to the reader device.

The system can further include a trusted computer system that, in someembodiments, can include a registration database and/or a server. Thetrusted computer system can be programmed to verify whether theidentifier received from the reader device is or is not associated withan authentic sensor control device. In some embodiments, theregistration database can include a plurality of identifiers and, foreach identifier within the plurality of identifiers, an indicationwhether the identifier is authentic. The registration database can alsoinclude one or more compilations of used and unused identifiers.

Also disclosed are example embodiments of methods of authenticationwithin in vivo analyte monitoring systems that can include receiving, bya reader device, an identifier from a sensor control device over a localwireless communication path, where the sensor control device includes asensor and analyte monitoring circuitry and the sensor is adapted to beinserted into the body of a user, and where the reader device includesmemory having a registration database stored thereon. The methods canfurther include determining authenticity of the identifier by referenceto the registration database, for example, by determining whether theidentifier is in the stored registration database and, if so, whetherthe identifier is associated with an unused device.

In some embodiments, the reader device commences or continues normaloperation with the sensor control device if the identifier is associatedwith an unused device, e.g., by receiving sensed analyte data from thesensor control device and/or displaying sensed analyte data from thesensor control device. If the identifier is associated with a devicethat has already been used or is counterfeit, then the reader device, incertain embodiments, does not operate with the sensor control device orterminates communications with the sensor control device.

Still other example embodiments are described of methods ofauthenticating in vivo analyte monitoring systems having a sensorcontrol device and a reader device. In these other embodiments, themethods can include receiving, by a reader device, an identifier from asensor control device over a local wireless communication path, wherethe sensor control device includes a sensor and analyte monitoringcircuitry, and where the sensor is adapted to be inserted into a body ofa user. The methods can also include receiving, by the reader device, afirst token, then determining, by the reader device, if the identifieris associated with an unused sensor control device by reference to aregistration database, and, if the identifier is associated with anunused sensor control device, then comparing, by the reader device, thefirst token with a second token stored in the registration database todetermine if the first and second tokens match.

In certain embodiments, if the identifier is not associated with anunused sensor control device, then operation with the sensor controldevice is ceased, and the user can be notified of the same. The readerdevice can operate with the sensor control device if the identifier isassociated with an unused device and the first and second token match.

If the first and second tokens match, then some embodiments of themethods can include reading, with the reader device, informationindicative of an analyte level of the user from the sensor controldevice and then displaying the analyte level on a display of the readerdevice.

Additional example embodiments are described of methods ofauthenticating an in vivo analyte monitoring system having a sensorcontrol device and a reader device. In these other embodiments, themethods can include receiving, by a reader device, an identifier fromthe sensor control device over a local wireless communication path,where the sensor control device includes a sensor and analyte monitoringcircuitry, and where the sensor is adapted to be inserted into a body ofa user. These embodiments can also include receiving a token at thereader device, where the token is known to be associated with the sensorcontrol device, sending the identifier and the token from the readerdevice over an internet to a trusted computer system having aregistration database, and receiving an authentication result from thetrusted computer system over the internet by the reader device, wherethe authentication result indicates whether the sensor control device isor is not authorized to operate with the reader device.

In certain embodiments, receiving the token, at the reader device,includes receiving the token from the sensor control device over thelocal wireless communication path, or using an optical scanner on thereader device to scan a barcode (e.g., 2D or 3D) on a package for thesensor control device, where the barcode is representative of the token,or using a near field communication (NFC) device to scan a package forthe sensor control device, where the package includes an element adaptedto provide information representative of the token in response to an NFCscan. The element can be, for example, an NFC tag. In other embodiments,the token can be printed on a package for the sensor control device andthe methods can include reading, by a human, the token from the package,and manually inputting the token into the reader device.

In certain embodiments, the methods can include determining, by thetrusted computer system, authenticity of the identifier and the token byreference to the registration database. For example, if the identifieris present in the registration database and associated with an unuseddevice, then it can be determined if the token received by the trustedcomputer system matches the token stored within the registrationdatabase. If the tokens match, then the sensor control device can beauthenticated.

In some embodiments, a plurality of tokens and identifiers are stored inthe registration database and only one token is associated with theidentifier. If the identifier is associated with an unused device, thencertain embodiments of the methods can include updating the registrationdatabase by associating the identifier with a used device.

In these and other embodiments, if the authentication result permitsoperation of the reader device with the sensor control device and if thesensor has been inserted into the body of the user, then the methods caninclude reading, with the reader device, information indicative of ananalyte level of the user from the sensor control device, and displayingthe analyte level on a display of the reader device.

Other example embodiments of systems, devices, and methods ofauthentication that use public and private keys are disclosed. Forexample, certain embodiments of these methods of authentication withinin vivo analyte monitoring systems can include providing a private keyto a reader device, where the private key is supplied by a sensorcontrol device or a package for the sensor control device, and where thesensor control device includes a sensor and analyte monitoring circuitryand the sensor is adapted to be inserted into the body of a user,authenticating the private key using a public key stored within thereader device, and if the private key is authenticated, reading sensedanalyte data from the sensor control device by the reader device.

In certain embodiments, providing the private key to the reader deviceincludes receiving, by the reader device, the private key from thesensor control device over the local wireless communication path,scanning a barcode (e.g., 2D or 3D) on a package for the sensor controldevice with an optical scanner of the reader device, where the barcodeis representative of the private key, or scanning a package for thesensor control device with a near field communication (NFC) device,where the package includes an element, e.g., an NFC tag, adapted toprovide information representative of the private key in response to theNFC scan. In other embodiments, the private key is printed on thepackage for the sensor control device and the methods can includereading, by a human, the private key from the package and manuallyinputting the private key into the reader device.

In still other embodiments, methods of authentication within in vivoanalyte monitoring systems can include digitally signing data with aprivate key, where the private key has a corresponding public key,storing the digitally signed data in the memory of a sensor controldevice, where the sensor control device includes a sensor and analytemonitoring circuitry and the sensor is configured to be inserted intothe body of a user, and storing the corresponding public key in thememory of a reader device, where the reader device is capable ofreceiving the digitally signed data from the sensor control device andis programmed to verify that the digitally signed data is authenticusing the public key.

In certain embodiments, the methods can also include determining atleast one calibration parameter for the sensor, where the data that isdigitally signed with the private key is the at least one calibrationparameter, and where the at least one calibration parameter isdetermined separately for each one of a plurality of sensor controldevices. Embodiments of the methods can also include storing the atleast one calibration parameter, in addition to the digitally signeddata, in the memory of the sensor control device. In some embodiments,the reader device is capable of receiving the at least one calibrationparameter from the sensor control device and is programmed to comparethe received at least one calibration parameter with the at least onecalibration parameter that was digitally signed. The reader device canbe programmed to operate normally with the sensor control device if thereceived at least one calibration parameter matches the at least onecalibration parameter that was digitally signed, and can be programmedto cease operation with the sensor control device if the received atleast one calibration parameter does not match the at least onecalibration parameter that was digitally signed.

In all embodiments described herein that operate with a digitalsignature or digitally signed data, that digital signature or digitallysigned data can be further encrypted prior to transfer between devicesand use in a verification process.

In certain embodiments, the methods can include receiving an identifierfrom the reader device, the identifier having been sent to the readerdevice by the sensor control device, determining, by reference to theregistration database, whether the identifier is or is not authentic,and sending an authentication result to the reader device, where theauthentication result indicates whether the identifier is or is notauthentic. The identifier can be determined to be authentic if it is notassociated with a used sensor control device or a counterfeit sensorcontrol device in the registration database. Certain embodiments of themethods can further include updating, if the identifier is determined tobe authentic, the registration database to reflect that the identifieris now associated with a used sensor control device and/or downloadingat least a portion of the registration database to the reader device.

In other embodiments, methods of authentication within in vivo analytemonitoring systems can include: receiving, by a reader device, digitallysigned data from a sensor control device, where the sensor controldevice includes a sensor and analyte monitoring circuitry and the sensoris configured to be inserted into the body of a user; using, by thereader device, a public key to verify whether the digitally signed datais authentic; and determining, by the reader device, whether anidentifier received from the sensor control device is or is notassociated with a sensor control device that has been used, by referenceto a local database stored in a memory of the reader device. In certainembodiments, the identifier is at least part of the digitally signeddata and is received from the sensor control device as the digitallysigned data.

For each and every embodiment of a method disclosed herein, systems anddevices capable of performing each of those embodiments are coveredwithin the scope of the present disclosure. For example, embodiments ofsensor control devices are disclosed and these devices can have one ormore sensors, analyte monitoring circuits (e.g., an analog circuit),memories, power sources, communication circuits, transmitters,receivers, processors and/or controllers that can be programmed toexecute any and all method steps or facilitate the execution of any andall method steps. These sensor control device embodiments can be usedand can be capable of use to implement those steps performed by a sensorcontrol device from any and all of the methods described herein.Likewise, embodiments of reader devices are disclosed having one or moretransmitters, receivers, memories, power sources, processors and/orcontrollers that can be programmed to execute any and all method stepsor facilitate the execution of any and all method steps. Theseembodiments of the reader devices can be used to implement those stepsperformed by a reader device from any and all of the methods describedherein. Embodiments of trusted computer systems are also disclosed.These trusted computer systems can include one or more processors,controllers, transmitters, receivers, memories, databases, servers,and/or networks, and can be discretely located or distributed acrossmultiple geographic locales. These embodiments of the trusted computersystems can be used to implement those steps performed by a trustedcomputer system from any and all of the methods described herein.

Other systems, devices, methods, features and advantages of the subjectmatter described herein will be or will become apparent to one withskill in the art upon examination of the following figures and detaileddescription. It is intended that all such additional systems, devices,methods, features and advantages be included within this description, bewithin the scope of the subject matter described herein, and beprotected by the accompanying claims. In no way should the features ofthe example embodiments be construed as limiting the appended claims,absent express recitation of those features in the claims.

BRIEF DESCRIPTION OF THE FIGURES

The details of the subject matter set forth herein, both as to itsstructure and operation, may be apparent by study of the accompanyingfigures, in which like reference numerals refer to like parts. Thecomponents in the figures are not necessarily to scale, emphasis insteadbeing placed upon illustrating the principles of the subject matter.Moreover, all illustrations are intended to convey concepts, whererelative sizes, shapes and other detailed attributes may be illustratedschematically rather than literally or precisely.

FIG. 1 is a high level diagram depicting an example embodiment of ananalyte monitoring system for real time analyte (e.g., glucose)measurement, data acquisition and/or processing.

FIG. 2A is a block diagram depicting an example embodiment of a readerdevice.

FIGS. 2B-C are block diagrams depicting example embodiments of a sensorcontrol device.

FIG. 3A is an illustration depicting an example embodiment of an in vivomonitoring system having authentication capability.

FIGS. 3B-C depict examples of data compilations, in human readable form,that could otherwise be stored, in machine-readable form, within anexample embodiment of a database.

FIG. 3D is an illustration depicting another example embodiment of an invivo monitoring system having authentication capability.

FIGS. 4-7 are illustrations depicting additional example embodiments ofin vivo monitoring systems having various authentication capabilities.

FIGS. 8A-C are flow diagrams depicting example embodiments of a methodof operating an in vivo monitoring system having authenticationcapability.

DETAILED DESCRIPTION

Before the present subject matter is described in detail, it is to beunderstood that this disclosure is not limited to the particularembodiments described, as such may, of course, vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting, since the scope of the present disclosure will be limited onlyby the appended claims.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present disclosure isnot entitled to antedate such publication by virtue of prior disclosure.Further, the dates of publication provided may be different from theactual publication dates which may need to be independently confirmed.

It should be noted that all features, elements, components, functions,and steps described with respect to any embodiment provided herein areintended to be freely combinable and substitutable with those from anyother embodiment. If a certain feature, element, component, function, orstep is described with respect to only one embodiment, then it should beunderstood that that feature, element, component, function, or step canbe used with every other embodiment described herein unless explicitlystated otherwise. This paragraph therefore serves as antecedent basisand written support for the introduction of claims, at any time, thatcombine features, elements, components, functions, and steps fromdifferent embodiments, or that substitute features, elements,components, functions, and steps from one embodiment with those ofanother, even if the following description does not explicitly state, ina particular instance, that such combinations or substitutions arepossible. It is explicitly acknowledged that express recitation of everypossible combination and substitution is overly burdensome, especiallygiven that the permissibility of each and every such combination andsubstitution will be readily recognized by those of ordinary skill inthe art.

Generally, embodiments of the present disclosure are used with in vivosystems, devices, and methods for detecting at least one analyte, suchas glucose, in body fluid, (e.g., subcutaneously within the ISF orblood, or within the dermal fluid of the dermal layer). Accordingly,many embodiments include in vivo analyte sensors arranged so that atleast a portion of the sensor is positioned in the body of a user toobtain information about at least one analyte of the body. It should benoted, however, that the embodiments disclosed herein can be used within vivo analyte monitoring systems that incorporate in vitro capability,as well has purely in vitro or ex vivo analyte monitoring systems.

As mentioned, a number of embodiments of systems, devices, and methodsare provided that allow for the authentication of components within anin vivo, in vitro, or ex vivo analyte monitoring environment. Theseembodiments can allow for the detection of unauthorized devices, ordevices supplied by other manufacturers, as well as to restrict thetypes of devices, regardless of manufacturer, that are used within theenvironment. Before describing these aspects of the embodiments indetail, however, it is first desirable to describe examples of devicesthat can be present within, for example, an in vivo analyte monitoringsystem, as well as examples of their operation.

Example Embodiments of In Vivo Analyte Monitoring Systems

FIG. 1 is an illustrative view depicting an example of an in vivoanalyte monitoring system 100 having a sensor control device 102 and areader device 120 that communicate with each other over a localcommunication path (or link) 140, which can be wired or wireless, anduni-directional or bi-directional. In embodiments where path 140 iswireless, a near field communication (NFC) protocol, RFID protocol,Bluetooth or Bluetooth Low Energy protocol, Wi-Fi protocol, proprietaryprotocol, or the like can be used, including those communicationprotocols in existence as of the date of this filing or their laterdeveloped variants.

Reader device 120 is also capable of wired, wireless, or combinedcommunication with a remote computer system 170 over communication path(or link) 141 and with trusted computer system 180 over communicationpath (or link) 142. Communication paths 141 and 142 can be part of atelecommunications network, such as a Wi-Fi network, a local areanetwork (LAN), a wide area network (WAN), the internet, or other datanetwork for uni-directional or bi-directional communication. In analternative embodiment, communication paths 141 and 142 can be the samepath. All communications over paths 140, 141, and 142 can be encryptedand sensor control device 102, reader device 120, remote computer system170, and trusted computer system 180 can each be configured to encryptand decrypt those communications sent and received.

Sensor control device 102 can include a housing 103 containing in vivoanalyte monitoring circuitry and a power source. The in vivo analytemonitoring circuitry is electrically coupled with an analyte sensor 104that extends through an adhesive patch 105 and projects away fromhousing 103. Adhesive patch 105 contains an adhesive layer (not shown)for attachment to a skin surface of the body of the user. (Other formsof body attachment to the body may be used, in addition to or instead ofadhesive.)

Sensor 104 is adapted to be at least partially inserted into the body ofthe user, where it can make fluid contact with that user's body fluid(e.g., interstitial fluid (ISF), dermal fluid, or blood) and be used,along with the in vivo analyte monitoring circuitry, to measureanalyte-related data of the user. Sensor 104 and any accompanying sensorcontrol electronics can be applied to the body in any desired manner.For example, also shown in FIG. 1 is an embodiment of insertion device150 that, when operated, transcutaneously (or subcutaneously) positionsa portion of analyte sensor 104 through the user's skin and into contactwith the bodily fluid, and positions sensor control device 102 withadhesive patch 105 onto the skin. In other embodiments, insertion device150 can position sensor 104 first, and then accompanying sensor controlelectronics can be coupled with sensor 104 afterwards, either manuallyor with the aid of a mechanical device. Other devices, systems, andmethods that may be used with embodiments herein, including variationsof sensor control device 102, are described, e.g., in U.S. PublicationNos. 2010/0324392, 2011/0106126, 2011/0190603, 2011/0191044,2011/0082484, 2011/0319729, and 2012/0197222, the disclosures of each ofwhich are incorporated herein by reference for all purposes.

After collecting the analyte-related data, sensor control device 102 canthen wirelessly communicate that data (such as, for example, datacorresponding to monitored analyte level and/or monitored temperaturedata, and/or stored historical analyte related data) to a reader device120 where, in certain embodiments, it can be algorithmically processedinto data representative of the analyte level of the user and thendisplayed to the user and/or otherwise incorporated into a diabetesmonitoring regime.

As shown in FIG. 1, reader device 120 includes a display 122 to outputinformation to the user and/or to accept an input from the user (e.g.,if configured as a touch screen), and one optional input component 121(or more), such as a button, actuator, touch sensitive switch,capacitive switch, pressure sensitive switch, jog wheel or the like, toinput data or commands to reader device 120 or otherwise control theoperation of reader device 120.

In certain embodiments, input component 121 of reader device 120 mayinclude a microphone and reader device 120 may include softwareconfigured to analyze audio input received from the microphone, suchthat functions and operation of the reader device 120 may be controlledby voice commands. In certain embodiments, an output component of readerdevice 120 includes a speaker (not shown) for outputting information asaudible signals. Similar voice responsive components such as a speaker,microphone and software routines to generate, process and store voicedriven signals may be provided to sensor control device 102.

In certain embodiments, display 122 and input component 121 may beintegrated into a single component, for example a display that candetect the presence and location of a physical contact touch upon thedisplay such as a touch screen user interface. In such embodiments, theuser may control the operation of reader device 120 by utilizing a setof pre-programmed motion commands, including, but not limited to, singleor double tapping the display, dragging a finger or instrument acrossthe display, motioning multiple fingers or instruments toward oneanother, motioning multiple fingers or instruments away from oneanother, etc. In certain embodiments, a display includes a touch screenhaving areas of pixels with single or dual function capacitive elementsthat serve as LCD elements and touch sensors.

Reader device 120 also includes one or more data communication ports 123for wired data communication with external devices such as a remoteterminal, e.g., a personal computer. Example data communication portsinclude USB ports, mini USB ports, RS-232 ports, Ethernet ports,Firewire ports, or other similar data communication ports configured toconnect to the compatible data cables. Reader device 120 may alsoinclude an integrated or attachable in vitro glucose meter, including anin vitro test strip port (not shown) to receive an in vitro glucose teststrip for performing in vitro blood glucose measurements.

Referring still to FIG. 1, display 122 can be configured to display avariety of information—some or all of which may be displayed at the sameor different time on display 122. The displayed information can beuser-selectable so that a user can customize the information shown on agiven display screen. Display 122 may include, but is not limited to,graphical display 138, for example, providing a graphical output ofglucose values over a monitored time period (which may show: markerssuch as meals, exercise, sleep, heart rate, blood pressure, etc.;numerical display 132, for example, providing monitored glucose values(acquired or received in response to the request for the information);and trend or directional arrow display 131 that indicates a rate ofanalyte change and/or a rate of the rate of analyte change, e.g., bymoving locations on display 122).

As further shown in FIG. 1, display 122 may also include: date display135, which can provide date information for the user; time of dayinformation display 139 providing time of day information to the user;battery level indicator display 133 graphically showing the condition ofthe battery (rechargeable or disposable) of reader device 120; sensorcalibration status icon display 134, for example, in monitoring systemsthat require periodic, routine or a predetermined number of usercalibration events notifying the user that the analyte sensorcalibration is necessary; audio/vibratory settings icon display 136 fordisplaying the status of the audio/vibratory output or alarm state; andwireless connectivity status icon display 137 that provides indicationof wireless communication connection with other devices such as sensorcontrol device 102, remote computer system 170, and/or trusted computersystem 180. Display 122 may further include simulated touch screenbuttons 125, 126 for accessing menus, changing display graph outputconfigurations or otherwise controlling the operation of reader device120.

In certain embodiments, reader device 120 can be configured to outputalarms, alert notifications, glucose values, etc., which may be visual,audible, tactile, or any combination thereof. Reader device 120 mayinclude other output components such as a speaker, vibratory outputcomponent and the like to provide audible and/or vibratory outputindications to the user in addition to the visual output indicationprovided on display 122. Further details and other display embodimentscan be found in, e.g., U.S. Publication No. 2011/0193704, which isincorporated herein by reference for all purposes.

Reader device 120 can be connected to a remote terminal 170, such as apersonal computer, which can be used by the user or a medicalprofessional to display and/or analyze the collected analyte data.Reader device 120 can also be connected to a trusted computer system 180that can be used for authentication of a third party softwareapplication. In both instances, reader device 120 can function as a dataconduit to transfer the stored analyte level information from the sensorcontrol device 102 to remote terminal 170 or trusted computer system180. In certain embodiments, the received data from the sensor controldevice 102 may be stored (permanently or temporarily) in one or morememories of reader device 120.

Remote terminal 170 may be a personal computer, a server terminal, alaptop computer, a tablet, or other suitable data processing device.Remote terminal 170 can be (or include) software for data management andanalysis and communication with the components in analyte monitoringsystem 100. Operation and use of remote terminal 170 is furtherdescribed in the '225 Publication incorporated herein (below). Analytemonitoring system 100 can also be configured to operate with a dataprocessing module (not shown), also as described in the incorporated'225 Publication.

Trusted computer system 180 can be within the possession of themanufacturer or distributor of sensor control device 102, eitherphysically or virtually through a secured connection, and can be used toperform authentication of sensor control device 102. Authentication ofsensor control device 102 can also be outsourced to a third-party, suchthat the third-party is physically in possession of trusted computersystem 180. Trusted computer system 180 is trusted in the sense thatsystem 100 can assume that it provides valid information anddeterminations upon which a foundation for the authentication activitiescan be based. Trusted computer system 180 can be trusted simply byvirtue of it being within the possession or control of the manufacturer,e.g., like a typical web server. Alternatively, trusted computer system180 can be implemented in a more secure fashion such as by requiringadditional password, encryption, firewall, or other internet accesssecurity enhancements that further guard against counterfeiter attacksor attacks by computer hackers.

Trusted computer system 180 can also be referred to as registrationcomputer system 180, or simply computer system 180. Trusted computersystem 180 can include one or more computers, servers, networks,databases, and the like.

In some embodiments, trusted computer system 180 includes a registrationdatabase 181, or has secure access to a registration database, whichcontains comprehensive registration information for all manufacturedsensor control devices 102. Upon the completion of the manufacturingprocess, authentication information about a particular sensor controldevice 102 can be stored within that sensor control device 102, placedon the packaging of that sensor control device 102, or otherwiseassociated with that sensor control device 102. This authenticationinformation can also be stored within registration database 181 oftrusted computer system 180 for future reference during a subsequentauthentication process for that sensor control device 102.

The authentication information can be in the form of a uniqueidentifier, where trusted computer system 180 can associate every uniqueidentifier with a different sensor control device 102, as well as anindication whether that sensor control device 102 has not yet been usedor has already been used. In these or other embodiments, authenticationinformation can be in the form of a pair of keys, such as a private keyand a public key, which are disseminated within system 100. In someembodiments, the private key is retained by trusted computer system 180and the public key is in the possession of reader device 120 (or sensorcontrol device 102). The keys themselves can be used for authentication,or they can be used to process digital signatures, e.g., digitally signand un-sign data, to verify the authenticity of reader device 120 (orsensor control device 102).

The processing of data within system 100 can be performed by one or morecontrol logic units or processors of reader device 120, remote terminal170, trusted computer system 180, and/or sensor control device 102. Forexample, raw data measured by sensor 104 can be algorithmicallyprocessed into a value that represents the analyte level and that isreadily suitable for display to the user, and this can occur in sensorcontrol device 102, reader device 120, remote terminal 170, or trustedcomputer system 180. This and any other information derived from the rawdata can be displayed in any of the manners described above (withrespect to display 122) on any display residing on any of sensor controldevice 102, reader device 120, remote terminal 170, or trusted computersystem 180.

The information may be utilized by the user to determine any necessarycorrective actions to ensure the analyte level remains within anacceptable and/or clinically safe range. Other visual indicators,including colors, flashing, fading, etc., as well as audio indicators,including a change in pitch, volume, or tone of an audio output, and/orvibratory or other tactile indicators may also be incorporated into theoutputting of trend data as means of notifying the user of the currentlevel, direction, and/or rate of change of the monitored analyte level.For example, based on a determined rate of glucose change, programmedclinically significant glucose threshold levels (e.g., hyperglycemicand/or hypoglycemic levels), and current analyte level derived by an invivo analyte sensor, an algorithm stored on a computer readable mediumof system 100 can be used to determine the time it will take to reach aclinically significant level and can be used to output a notification inadvance of reaching the clinically significant level, e.g., 30 minutesbefore a clinically significant level is anticipated, and/or 20 minutes,and/or 10 minutes, and/or 5 minutes, and/or 3 minutes, and/or 1 minute,and so on, with outputs increasing in intensity or the like.

Referring now in further detail to reader device 120, that device 120can be a mobile communication device such as a mobile telephoneincluding, but not limited to, a Wi-Fi or internet enabled smart phone,tablet, or personal digital assistant (PDA). Examples of smart phonescan include those mobile phones based on a Windows® operating system,Android™ operating system, iPhone® operating system, Palm® WebOS™,Blackberry® operating system, or Symbian® operating system, with datanetwork connectivity functionality for data communication over aninternet connection and/or a local area network (LAN).

Reader device 120 can also be configured as a mobile smart wearableelectronics assembly, such as an optical assembly that is worn over oradjacent to the user's eye (e.g., a smart glass or smart glasses, suchas Google glasses, which is a mobile communication device). This opticalassembly can have a transparent display that displays information aboutthe user's analyte level (as described herein) to the user while at thesame time allowing the user to see through the display such that theuser's overall vision is minimally obstructed. The optical assembly maybe capable of wireless communications similar to a smart phone. Otherexamples of wearable electronics include devices that are worn around orin the proximity of the user's wrist (e.g., a watch, etc.), neck (e.g.,a necklace, etc.), head (e.g., a headband, hat, etc.), chest, or thelike.

FIG. 2A is a block diagram of an example embodiment of a reader device120 configured as a smart phone. Here, reader device 120 includes aninput component 121, display 122, and processing hardware 226, which caninclude one or more processors, microprocessors, controllers, and/ormicrocontrollers, each of which can be a discrete chip or distributedamongst (and a portion of) a number of different chips. Here, processinghardware 226 includes a communications processor 222 having on-boardmemory 223 and an applications processor 224 having on-board memory 225.Reader device 120 further includes an RF transceiver 228 coupled with anRF antenna 229, a memory 230, multi-functional circuitry 232 with one ormore associated antennas 234, a power supply 236, and power managementcircuitry 238. FIG. 2A is an abbreviated representation of the typicalhardware and functionality that resides within a smart phone and thoseof ordinary skill in the art will readily recognize that other hardwareand functionality (e.g., codecs, drivers, glue logic, can also beincluded here.

Communications processor 222 can interface with RF transceiver 228 andperform analog-to-digital conversions, encoding and decoding, digitalsignal processing and other functions that facilitate the conversion ofvoice, video, and data signals into a format (e.g., in-phase andquadrature) suitable for provision to RF transceiver 228, which can thentransmit the signals wirelessly. Communications processor 222 can alsointerface with RF transceiver 228 to perform the reverse functionsnecessary to receive a wireless transmission and convert it into digitaldata, voice, and video.

Applications processor 224 can be adapted to execute the operatingsystem and any software applications that reside on reader device 120,process video and graphics, and perform those other functions notrelated to the processing of communications transmitted and receivedover RF antenna 229. The smart phone operating system will operate inconjunction with a number of applications on reader device 120. Anynumber of applications can be running on reader device 120 at any onetime, and will typically include one or more applications that arerelated to a diabetes monitoring regime, in addition to the othercommonly used applications that are unrelated to such a regime, e.g.,email, calendar, weather, sports, games, etc.

Memory 230 can be shared by one or more the various functional unitspresent within reader device 120, or can be distributed amongst two ormore of them (e.g., as separate memories present within differentchips). Memory 230 can also be a separate chip of its own. Memory 230 isnon-transitory, and can be volatile (e.g., RAM, etc.) and/ornon-volatile memory (e.g., ROM, flash memory, F-RAM, etc.).

Multi-functional circuitry 232 can be implemented as one or more chipsand/or components (e.g., transmitter, receiver, transceiver, and/orother communication circuitry) that perform other functions such aslocal wireless communications (e.g., for Wi-Fi, Bluetooth, Bluetooth LowEnergy, Near Field Communication (NFC), Radio Frequency Identification(RFID), and others) and determining the geographic position of readerdevice 120 (e.g., global positioning system (GPS) hardware). One or moreother antennas 234 are associated with the functional circuitry 232 asneeded to operate with the various protocols and circuits.

Power supply 236 can include one or more batteries, which can berechargeable or single-use disposable batteries. Power managementcircuitry 238 can regulate battery charging and power supply monitoring,boost power, perform DC conversions, and the like.

As mentioned, the reader device 120 may also include one or more datacommunication ports such as USB port (or connector) or RS-232 port (orany other wired communication ports) for data communication with aremote terminal 170, trusted computer system 180, or sensor controldevice 102, to name a few.

Reader device 120 may include a strip port (not shown) or be coupledwith a strip port module (not shown) configured to receive in vitro teststrips. In such a configuration, reader device 120 can process a fluidsample on a test strip, determine an analyte level contained therein,and display that result to a user. Any suitable in vitro test strip maybe employed, e.g., test strips that only require a very small amount(e.g., one microliter or less, e.g., about 0.5 microliter or less, e.g.,about 0.1 microliter or less), of applied sample to the strip in orderto obtain accurate glucose information, e.g. FreeStyle® or Precision®blood glucose test strips and systems from Abbott Diabetes Care Inc.Reader devices with in vitro monitors and test strip ports may beconfigured to conduct in vitro analyte monitoring with no usercalibration in vitro test strips (i.e., no human interventioncalibration), such as FreeStyle Lite glucose test strips from AbbottDiabetes Care Inc. Detailed description of such test strips and devicesfor conducting in vitro analyte monitoring is provided in U.S. Pat. Nos.6,377,894, 6,616,819, 7,749,740, 7,418,285; U.S. Published PatentPublication Nos. 2004/0118704, 2006/0091006, 2008/0066305, 2008/0267823,2010/0094110, 2010/0094111, and 2010/0094112, and 2011/0184264, thedisclosure of each of which are incorporated herein by reference for allpurposes. The present inventive subject matter can be used with and/orin the systems, devices, and methods described in these incorporatedreferences.

FIGS. 2B-C are block schematic diagrams depicting example embodiments ofsensor control device 102 having analyte sensor 104 and sensorelectronics 110 (including analyte monitoring circuitry) that can havethe majority of the processing capability for rendering end-result datasuitable for display to the user. In FIG. 2B, a single semiconductorchip 201 is depicted that can be a custom application specificintegrated circuit (ASIC). Shown within ASIC 201 are certain high-levelfunctional units, including an analog front end (AFE) 202, powermanagement (or control) circuitry 204, processor 206, and communicationcircuitry 208 (which can be implemented as a transmitter, receiver,transceiver, passive circuit, or otherwise according to thecommunication protocol). In this embodiment, both AFE 202 and processor206 are used as analyte monitoring circuitry, but in other embodimentseither circuit can perform the analyte monitoring function. Processor206 can include one or more processors, microprocessors, controllers,and/or microcontrollers, each of which can be a discrete chip ordistributed amongst (and a portion of) a number of different chips.

A memory 203 is also included within ASIC 201 and can be shared by thevarious functional units present within ASIC 201, or can be distributedamongst two or more of them. Memory 203 can also be a separate chip.Memory 203 can be volatile and/or non-volatile memory. In thisembodiment, ASIC 201 is coupled with power source 210, which can be acoin cell battery, or the like. AFE 202 interfaces with in vivo analytesensor 104 and receives measurement data therefrom and outputs the datato processor 206 in digital form, which in turn processes the data toarrive at the end-result glucose discrete and trend values, etc. Thisdata can then be provided to communication circuitry 208 for sending, byway of antenna 211, to reader device 120 (not shown) where minimalfurther processing is needed by the resident software application todisplay the data.

FIG. 2C is similar to FIG. 2B but instead includes two discretesemiconductor chips 212 and 214, which can be packaged together orseparately. Here, AFE 202 is resident on ASIC 212. Processor 206 isintegrated with power management circuitry 204 and communicationcircuitry 208 on chip 214. AFE 202 includes memory 203 and chip 214includes memory 205, which can be isolated or distributed within. In oneexample embodiment, AFE 202 is combined with power management circuitry204 and processor 206 on one chip, while communication circuitry 208 ison a separate chip. In another example embodiment, both AFE 202 andcommunication circuitry 208 are on one chip, and processor 206 and powermanagement circuitry 204 are on another chip. It should be noted thatother chip combinations are possible, including three or more chips,each bearing responsibility for the separate functions described, orsharing one or more functions for fail-safe redundancy.

Performance of the data processing functions within the electronics ofthe sensor control device 102 provides the flexibility for system 100 toschedule communication from sensor control device 102 to reader device120, which in turn limits the number of unnecessary communications andcan provide further power savings at sensor control device 102.

Information may be communicated from sensor control device 102 to readerdevice 120 automatically and/or continuously when the analyteinformation is available, or may not be communicated automaticallyand/or continuously, but rather stored or logged in a memory of sensorcontrol device 102, e.g., for later output. Accordingly, in manyembodiments of system 100, analyte information derived by sensor controldevice 102 is made available in a user-usable or viewable form only whenqueried by the user such that the timing of data communication isselected by the user.

Data can be sent from sensor control device 102 to reader device 120 atthe initiative of either sensor control device 102 or reader device 120.For example, in some example embodiments sensor control device 102 cancommunicate data periodically in a broadcast-type fashion, such that aneligible reader device 120, if in range and in a listening state, canreceive the communicated data (e.g., sensed analyte data). This is atthe initiative of sensor control device 102 because reader device 120does not have to send a request or other transmission that first promptssensor control device 102 to communicate. Broadcasts can be performed,for example, using an active Wi-Fi, Bluetooth, or BTLE connection. Thebroadcasts can occur according to a schedule that is programmed withindevice 102 (e.g., about every 1 minute, about every 5 minutes, aboutevery 10 minutes, or the like). Broadcasts can also occur in a random orpseudorandom fashion, such as whenever sensor control device 102 detectsa change in the sensed analyte data. Further, broadcasts can occur in arepeated fashion regardless of whether each broadcast is actuallyreceived by a reader device 120.

System 100 can also be configured such that reader device 120 sends atransmission that prompts sensor control device 102 to communicate itsdata to reader device 120. This is generally referred to as “on-demand”data transfer. An on-demand data transfer can be initiated based on aschedule stored in the memory of reader device 120, or at the behest ofthe user via a user interface of reader device 120. For example, if theuser wants to check his or her analyte level, the user could perform ascan of sensor control device 102 using an NFC, Bluetooth, BTLE, orWi-Fi connection. Data exchange can be accomplished using broadcastsonly, on-demand transfers only, or any combination thereof.

Accordingly, once a sensor control device 102 is placed on the body sothat at least a portion of sensor 104 is in contact with the bodilyfluid and electrically coupled to the electronics within device 102,sensor derived analyte information may be communicated in on-demand orbroadcast fashion from the sensor control device 102 to a reader device120. On-demand transfer can occur by first powering on reader device 120(or it may be continually powered) and executing a software algorithmstored in and accessed from a memory of reader device 120 to generateone or more requests, commands, control signals, or data packets to sendto sensor control device 102. The software algorithm executed under, forexample, the control of processing hardware 226 of reader device 120 mayinclude routines to detect the position of the sensor control device 102relative to reader device 120 to initiate the transmission of thegenerated request command, control signal and/or data packet.

Different types and/or forms and/or amounts of information may be sentas part of each on-demand or broadcast transmission including, but notlimited to, one or more of current analyte level information (i.e., realtime or the most recently obtained analyte level information temporallycorresponding to the time the reading is initiated), rate of change ofan analyte over a predetermined time period, rate of the rate of changeof an analyte (acceleration in the rate of change), or historicalanalyte information corresponding to analyte information obtained priorto a given reading and stored in a memory of sensor control device 102.

Some or all of real time, historical, rate of change, rate of rate ofchange (such as acceleration or deceleration) information may be sent toreader device 120 in a given communication or transmission. In certainembodiments, the type and/or form and/or amount of information sent toreader device 120 may be preprogrammed and/or unchangeable (e.g., presetat manufacturing), or may not be preprogrammed and/or unchangeable sothat it may be selectable and/or changeable in the field one or moretimes (e.g., by activating a switch of the system, etc.). Accordingly,in certain embodiments, reader device 120 will output a current (realtime) sensor-derived analyte value (e.g., in numerical format), acurrent rate of analyte change (e.g., in the form of an analyte rateindicator such as an arrow pointing in a direction to indicate thecurrent rate), and analyte trend history data based on sensor readingsacquired by and stored in memory of sensor control device 102 (e.g., inthe form of a graphical trace). Additionally, an on-skin or sensortemperature reading or measurement may be communicated from sensorcontrol device 102 with each data communication. The temperature readingor measurement, however, may be used in conjunction with a softwareroutine executed by reader device 120 to correct or compensate theanalyte measurement output to the user by reader device 120, instead ofor in addition to actually displaying the temperature measurement to theuser.

US Patent Application Publication No. 2011/0213225 (the '225Publication) generally describes components of an in vivo-based analytemonitoring system that are suitable for use with the authenticationmethods and hardware embodiments described herein. The '225 Publicationis incorporated by reference herein in its entirety for all purposes.For other examples of sensor control device 102 and reader device 120,see, e.g., devices 102 and 120, respectively, as described in theincorporated '225 Publication.

Example Embodiments of Authentication Systems, Devices, and Methods

In many conventional in vivo systems, the sensor control device andreader device communicate with each other over a proprietary wirelessprotocol that cannot easily be deciphered by third parties. The presenceof this proprietary wireless protocol acts as a barrier to the usage ofunauthorized sensor control or reader devices within the in vivo system.

However, with the integration of in vivo monitoring software intocommercially available communication devices like smart phones and theuse of those smart phones to communicate with the sensor control deviceusing well known communication protocols (e.g., Wi-Fi, NFC, RFID,Bluetooth, BTLE, etc.), the proprietary communication link can no longeract as a de facto technique for authentication. Accordingly, othertechniques and hardware for authentication are required.

A number of example embodiments of enhanced systems, devices, andmethods for providing authentication are described herein. In theseembodiments, the device being authenticated will most commonly be sensorcontrol device 102. It should be understood, however, that thetechniques and features described herein can also be used toauthenticate other devices and components of system 100 other thansensor control device 102. For instance, in certain embodiments, readerdevice 120 can be authenticated using similar techniques and features tothose described herein.

Generally, to operate in vivo monitoring system 100, a user will firstremove, or cause to be removed, sensor control device 102 from sterilepackaging. Sensor control device 102 can then be placed on the user'sbody such that sensor 104 is in contact with the user's body fluid. Asmentioned, this can be done with the aid of an inserter 150. In manyembodiments, sensor control device 102 will be activated as will readerdevice 120. A connection will also be established between sensor controldevice 102 and reader device 120 so that they may exchange data andinformation. These events can occur in a number of different sequences.For instance, activation of sensor control device 102 can occur prior toremoval from packaging, upon the removal from packaging, or subsequentto the removal from packaging (either before or after placement on theuser's body). Activation of reader device 120 can also occur at any ofthose times. Reader device 120, in some embodiments can be a smartphone, in which case it will likely have been activated long beforeactivation of sensor control device 102. In fact, reader device 120 mayhave interfaced with any number of sensor control devices 102 prior tothe current one. By way of further example, the connection betweensensor control device 102 and reader device 120 can be established priorto the removal of sensor control device 102 from its packaging, upon theremoval of sensor control device 102 from its packaging, or subsequentto the removal of sensor control device 102 from its packaging (eitherbefore or after placement of sensor control device 102 on the user'sbody).

Authentication of sensor control device 102 can also occur at any timeduring the usage of that sensor control device 102. For instance,authentication can occur prior to the removal of sensor control device102 from its packaging, upon removal of sensor control device 102 fromits packaging, or subsequent to removal of sensor control device 102from its packaging (either before or after placement of sensor controldevice 102 on the user's body). Authentication can occur during theestablishment of a connection between sensor control device 102 andreader device 120, for example, during or immediately after the pairingof sensor control device 102 with reader device 120 if a pairingprocedure is used, such as with a Bluetooth protocol. Authentication canoccur after establishing a connection between sensor control device 102and reader device 120 but prior to the monitoring of analyte levels bysensor control device 102, or prior to the reception of those monitoredanalyte levels by reader device 120.

In still other embodiments, authentication can occur after sensorcontrol device 102 has monitored the analyte levels, transferred thoseanalyte levels to reader device 120, and reader device 120 has displayedthose analyte levels to the user or otherwise communicated them to theuser or to another computer system for display and/or analysis. In mostembodiments, the purpose of authentication of sensor control device 102is to detect the presence of counterfeit sensor control devices andprevent their usage in system 100, meaning that authentication providesthe greatest benefits when it occurs prior to actual use of sensorcontrol device 102 to measure and/or communicate measured analyte levelsof the user. Thus, while delay in the authentication process ispermissible, it may not be the most desirable (depending on theimplementation).

The authentication process can be initiated by either sensor controldevice 102 or reader device 120. For instance, reader device 120 cansend an identification request or command to sensor control device 102so that sensor control device 102 can initiate the authenticationprocess, for instance, by sending authentication information to readerdevice 120. The identification request or command need not be dedicatedfor the purpose of initiating the authentication process. Rather, therequest or command can instead be data, e.g., header or payload data,that is used primarily for other purposes but is interpreted, e.g., uponinitial receipt, as a trigger for the sending of authenticationinformation by sensor control device 102.

Alternatively, sensor control device 102 can initiate the authenticationprocess by automatically supplying authentication information to readerdevice 120 without having received a prior request to do so. Sensorcontrol device 102 may broadcast authentication information uponactivation, or upon establishing a connection with reader device 120,upon receiving a first communication from reader device 120, or thelike. Sensor control device 102 can also be configured to continuouslysend authentication information until the receipt of an acknowledgmentfrom reader device 120. Sensor control device 102 may includeauthentication information within all (or most) communications as amatter of course, to allow reader device 120 to read the authenticationinformation when desired, and also to allow multiple reader devices 120to operate with sensor control device 102 without having to sendmultiple authentication information requests.

FIG. 3A is an illustration depicting an example embodiment of in vivoanalyte monitoring system 100. Here, sensor control device 102 is incommunication with reader device 120 over a local wireless communicationpath 140. Reader device 120 is in communication with trusted computersystem 180 over communication path 142, which in this embodiment is theinternet. Sensor control device 102 includes a memory (e.g., memory 203and/or 205 as shown in FIGS. 2B-C) that stores authenticationinformation about sensor control device 102. This authenticationinformation can, in certain embodiments, uniquely identify sensorcontrol device 102 such that no two sensor control devices 102 (withinthe same product line) share the same authentication information. Inmany embodiments, the authentication information is an identification(ID) number of sensor control device 102 or sensor 104 (also referred toherein as an “identifier”), e.g., a serial number, that is assigned tosensor control device 102 and stored within memory 203 and/or 205 duringthe manufacturing or post manufacturing process. Identifiers 304 can bechosen as a non-sequential, random, or pseudo-random string ofcharacters (alphanumeric or otherwise) to minimize the risk that acounterfeiter will be able to forecast or correctly guess futureidentifiers 304.

FIG. 3A depicts system 100 with the sending of communications atdifferent points in time. For example, reader device 120 first transmitscommunication 301 (or transmission, message, packet, etc.), containingan authentication request 302, to sensor control device 102 overcommunication path 140. After receiving and reading authenticationrequest 302, sensor control device 102 can send a communication 303,containing identifier 304, back to reader device 120 over path 140.Reader device 120, after receiving identifier 304, can optionallyperform a first verification to ensure that identifier 304 is in theproper format or that identifier 304 does not belong to a class ofdevices (e.g., prior models) that are not for operation with readerdevice 120.

Reader device 120 can then transmit a communication 305, containingidentifier 304 (in the same or a different format from that received),over communication path 142 to trusted computer system 180. Trustedcomputer system 180 includes computer hardware that is programmed toread the received identifier 304 and compare it to a compilation ofidentifiers stored therewith, such as within registration database 181.The compilation can be in any desired form, including but not limited toa data structure, table, list, array, and the like. The compilation canalso be contiguous or non-contiguous, e.g., spread across multiple datastructures. In certain embodiments, each identifier stored withinregistration database 181 is associated with an indication as to whetherthat identifier correlates to a sensor control device 102 that hasalready been used.

FIG. 3B depicts an example of a compilation 182 of identifiers 304 in atable format. In most embodiments, compilation 304 would be stored in acomputer readable format different from the human readable format shownhere. Each identifier 304 is contained within one of two separate lists:a first list 184 of identifiers 304 that are associated with sensorcontrol devices 102 that have already been used; or a second list 186 ofidentifiers 304 that are associated with sensor control devices 102 thathave not yet been used. Trusted computer system 180 can consult thecompilation of unused sensor control devices 102 first and thecompilation of used sensor control devices 102 second or vice-versa.

Alternatively, compilation 182 can include only unused identifiers 304,where a failure to locate the received identifier 304 within thatcompilation corresponds to a conclusion that the received identifier 304is associated with an already used sensor control device 102, a sensorcontrol device 102 that is not authorized for use with reader device120, or a sensor control device 102 that is counterfeit. Once aparticular identifier 304 is located within the compilation it wouldthen be removed. Of course, a reverse scheme can also be implementedwhere compilation 182 only includes used identifiers 304.

Should a received identifier 304 be located on list 186, then trustedcomputer system 180 associates that received identifier 304 with asensor control device 102 that is authentic (e.g., not made by adifferent manufacturer), or authorized for use by the user with readerdevice 120. Trusted computer system 180 then generates an authenticationresult 306 that authorizes the use of sensor control device 102 andtransmits that authentication result 306 in communication 307 overcommunication path 142 to reader device 120. Authentication result 306can be one or more bits of data (e.g., a flag or notification) thatindicate whether or not sensor control device 102 is permitted for use,and also optionally any other related information, such as the reason(s)for a failure to authenticate. Authentication result 306 can beinterpreted by reader device 120 as a command to continue or to stopoperation with sensor control device 102.

Trusted computer system 180 also revises compilation 182 such that thereceived identifier 304 is then associated with a used sensor controldevice 102. In this embodiment, this would entail moving that identifier304 from list 186 to list 184. Reader device 120 receives and reads theauthentication result 306, thereby becoming informed that sensor controldevice 102 is an authentic device.

Reader device 120 can then optionally display the positiveauthentication result to the user. Reader device 120 can be programmedto then initiate (or, alternatively, to then continue) normal operationwith sensor control device 102, such as by receiving monitored analytedata from sensor control device 102 and displaying that information,e.g., in the form of a glucose level, to the user.

Alternatively, should a received identifier 304 be located on list 184,then trusted computer system 180 associates that received identifierwith a sensor control device 102 that is not authentic, or notauthorized for use by the user with reader device 120. In such aninstance, it is possible that sensor control device 102 is an unusedcounterfeit device, that sensor control device 102 had already been usedonce and an attempt is being made to reuse that same sensor controldevice 102, or that sensor control device 102 is a refurbished orrecycled device. Other possibilities may also exist. Trusted computersystem 180 then generates an authentication result 306 that indicatesthat the use of sensor control device 102 is not permitted orauthorized, and transmits that negative authentication result 306 overcommunication path 142 to reader device 120. Reader device 120 receivesand reads the authentication result 306, thereby becoming informed thatsensor control device 102 is not authorized. Reader device 120 can beprogrammed to then cease operation with sensor control device 102, orotherwise prevent the use of that particular sensor control device 102.Reader device 120 can optionally display the negative authenticationresult to the user and instruct the user to remove sensor control device102 if it has already been applied to the user's body. Reader device 120can optionally inform the user that the sensor control device is acounterfeit device.

In some embodiments, reader device 120 includes local positioningcapability that determines its geographic position. Because the readerdevice 120 is typically used in close proximity with sensor controldevice 102, e.g., by the same user, it can be assumed that sensorcontrol device 102 will have the same geographic location has readerdevice 120. Referring back to FIG. 3A, reader device 120 can transmitcurrent location information along with identifier 304 in communication305. The current location information can be used by trusted computersystem 180 to assess whether sensor control device 102 is being usedwithin an authorized geographic region. Authorized geographic regionscan be segmented on the basis of continents, nations, or other regionsas desired. Such an assessment can help ensure that sensor controldevice 102 is used only in regions where the device has regulatory orother requisite governmental approval.

FIG. 3C depicts an example embodiment of compilation 182 having regionalinformation further included therein. In this embodiment, list 186includes those identifiers 304 that are associated with unused sensorcontrol devices 102 within a first partition 187 and those regions inwhich the corresponding sensor control device 102 is approved for usewithin a second partition 188. Thus, if identifier 304 is located bysystem 180 within partition 187 of list 186, then system 180 can furthercompare the received location information with the approved regions inpartition 188. If it is determined that the current location of theunused sensor control device 102 is within an approved region, thentrusted computer system 180 can generate a positive authenticationresult 306 (an approval indication) and transmit that positiveauthentication result 306 to reader device 120. Reader device 120 canthen treat sensor control device 102 as an authorized device. Should itbe determined that the current location of the unused sensor controldevice 102 is not within an approved region, then trusted computersystem 180 can generate a negative authentication result 306 (withheldauthorization) and transmit that result 306 to reader device 120.

Alternatively, system 180 can generate a hybrid authentication result306 that indicates that sensor control device 102 is authentic but notin the proper region. Reader device 120 can be programmed to allowtemporary use of sensor control device 102 in the improper region, forexample, if the user is traveling. Reader device 120 can cease operationwith sensor control device 102 and, optionally display or otherwisecommunicate that result to the user.

In other embodiments, reader device 120 can locally store informationthat correlates particular sensor control devices 102 with the regionsin which they are approved for use. In those cases, reader device 120can locally determine whether a particular sensor control device 102 isapproved for use in a particular region without having to communicatefirst with another computer system over the internet to obtain thatauthorization.

FIG. 3D is an illustration depicting another example embodiment ofsystem 100. This embodiment is similar to that described with respect toFIG. 3A except that reader device 120 locally stores a registrationdatabase 129 (similar to registration database 181) and can useregistration database 129 to perform an authentication of sensor controldevice 102 without the need for an internet connection to a remotenetwork having trusted computer system 180. Thus, reader device 120 neednot always have internet access to perform authentication, therebyallowing the user added flexibility in using system 100. Database 129 isstored within the local memory (e.g., memory 263 as depicted in FIG. 2B)of reader device 120, for example, during manufacturing, and can beaccessed at any time. Similar to the embodiments described above, readerdevice 120 can, optionally, first send an authentication request 302 tosensor control device 102 in communication 301. Sensor control device102 can then respond with identifier 304 in communication 303. Afterreceiving identifier 304, reader device 120 can consult database 129 todetermine if identifier 304 is associated with a used or unused devicein a manner similar to that described with respect to FIGS. 3A-C.

Local registration database 129 can be updated once an internetconnection is established by reader device 120. In another embodiment,new sensor control devices 102 (e.g., individually or in a multi-pack)can be provided to users with updates to local registration database 129stored therein, where those updates are subsequently communicatedwirelessly or otherwise uploaded to reader device 120. In yet anotherembodiment, the updates to database 129 can be provided with new sensorcontrol devices 102 by way of barcodes or NFC (or RFID) elements thatcontain the updates and can provide the update to reader device 120through a corresponding optical, NFC, or RFID scan.

In an update, identifiers 304 associated with newly manufactured sensorcontrol devices 102 can be appended to database 129, and those sensorcontrol devices 102 that were marked as unused within database 129,which have recently been used by a user, can be updated accordinglywithin database 129. In addition, when an internet connection isestablished, reader device 120 can report the fact that identifier 304of the current sensor control device 102 has now been used to trustedcomputer system 180 so that it may update database 181 and report thesame to other reader devices 120 in the field.

In certain embodiments, database 181 acts as a master database that canbe used to resolve any conflicts between databases 129 of reader devices120 in the field. Trusted computer system 180 can also send a message orcommand to a particular reader device 120 that has been used with acounterfeit or unauthorized sensor control device 102 that instructsthat reader device 120 to establish an internet connection prior tocommencing normal operation (e.g., reading and reporting sensed analytedata) with any future sensor control devices 102. This can effectivelydesignate those reader devices 120 that have been used with counterfeitsensor control devices 102 as higher risk devices that may be morelikely to be used with counterfeit sensor control devices 102 in thefuture. The more stringent safeguard is the requirement that thosereader devices 120 establish an interconnect connection and perform anauthentication procedure with trusted computer system 180 prior tocommencing normal operation with any particular sensor control device102.

FIGS. 4 and 5A-B are illustrations depicting additional exampleembodiments of system 100 and the use thereof. In these embodiments,system 100 utilizes both an identifier 304 and a token 402. Token 402,in most embodiments, is a unique value associated with identifier 304for a particular sensor control device 102 during the manufacturingprocess, and is stored together with identifier 304 within the memory ofsensor control device 102. In many cases, one and only one token 402 isassociated with each identifier 304. However, in some instances it maybe desirable to associate multiple tokens 402 with a single identifier304, or multiple identifiers 304 with a single token 402. Token 402 canbe chosen as a non-sequential, random, or pseudo-random string ofcharacters (alphanumeric or otherwise) to minimize the risk that a thirdparty will be able to forecast or correctly guess future tokens 402.

Generally, for purposes of authentication, the identifier 304 and token402 are obtained from a particular sensor control device 102 (or itspackaging, etc.) and input into reader 120. This obtained identifier 304can then be used as an index to look up and retrieve a correspondingtoken 402 from a registration database, and this retrieved token 402 iscompared with the token 402 obtained from the particular sensor controldevice 102 to determine if they match. A match can be treated asauthentication of the sensor control device 102, and a mismatch can betreated as indicative of a counterfeit, reused, recycled, refurbished,or otherwise unauthorized sensor control device 102.

These embodiments may find particular suitability in implementationswhere identifier 304 is a non-random (e.g., sequential) serial number ofthe sensor control device 102 that might be predictable to a thirdparty. The use of an additional random, non-sequential string ofcharacters in the form of token 402 makes it more difficult, if notimpossible, for third parties to accurately predict the token and forgesensor control devices 102.

Token 402 can be provided to reader device 120 in a number of differentways. In the embodiment of FIG. 4, token 402 is provided directly toreader 120 by sensor control device 102. Like the embodiments describedwith respect to FIGS. 3A and 3D, reader device 120 can send anidentifier request 302 to sensor control device 102 in communication301. Sensor control device 102 can respond by retrieving both anidentifier 304 and a token 402 from memory and communicating theidentifier 304 and token 402 to reader device 120 in communication 404.Reader device 120 can then send identifier 304 and token 402 to trustedcomputer system 180 in communication 406.

Trusted computer system 180 can verify the received identifier 304against registration database 181 in a manner similar to that alreadydescribed. In addition, or in the alternative, trusted computer system180 can use identifier 304 as an index to locate and retrieve a token402 that was associated with that specific identifier 304 by themanufacturer, for example, during the manufacturing process. Token 402can be stored within database 181 as a data element associated withidentifier 304 within a particular data structure, or in separate memorylocated outside of database 181 (within trusted computer system 180 orelsewhere).

The token 402 that is retrieved from database 181 can then be comparedto the token 402 provided by reader device 120. If the two tokens 402match, a positive authentication result 306 is generated and transmittedto reader device 120 in communication 408. Reader device 120 can beprogrammed to commence or continue normal operation with sensor controldevice 120 if a positive authentication result 306 is received. If thetwo tokens 402 do not match, then it is possible that sensor controldevice 120 is a counterfeit device (or a reused, refurbished, orrecycled device, etc.) and authorization is withheld. A negativeauthentication result 306 is generated and transmitted to reader device120 (in communication 408) instructing it to cease or terminate normaloperation with sensor control device 102. Reader device 120 can,optionally, instruct the user of the same.

FIGS. 5A-B depict an alternative embodiment where token 402 is notprovided directly by sensor control device 102, but rather is obtainedindirectly with the assistance of the user. In FIG. 5A, sensor controldevice 102 is depicted within packaging 501. Packaging 501 includes acode 502 such as printed barcode 502 with information corresponding totoken 402. An optical scanner 505 (e.g., a camera) of reader device 120can optically scan barcode 502 to retrieve token 402.

Packaging 501 can be a container for any part of system 100 that issupplied to the user, and is not limited to the container for the actualsensor control device 102, itself. Packaging 501 can be a container forsensor control device 102 alone, a container for multiple sensor controldevices 102 (e.g., a multi-pack), a container for sensor control device102 in combination with inserter 150 (FIG. 1), a container for inserter150 alone, and can refer to inserts, labels, instructions, manuals, orthe like that are contained within or otherwise shipped with system 100.Barcode 502 is shown here as a two-dimensional barcode. Barcode 502 canalso be a one-dimensional barcode, three-dimensional barcode and can beof any format (QR code, data matrix, maxicode, aztec code, QR code,etc.). Printed indicia other than barcodes can be used as well.

Any number of additional techniques can be used to provide token 402 toreader device 120. For example, token 402 can be printed in humanreadable form on package 501, e.g., on a holographic label, such thatthe user can manually enter token 402 into reader device 120. In anotherexample, token 402 is stored in an RFID (or NFC) label on packaging 501and is read using an RFID (or NFC) scanner that is part of reader device120. Many smart phones that can serve as reader devices 120 are equippedwith RFID or NFC scanners that can read such labels. Othermachine-readable formats can be used to obtain token 402 from packaging501 as well. In all of the examples described herein, the provision oftoken 402 to reader device 120 can be done at a time of the user'schoosing or in response to a prompt to do so by reader device 120.

Turning to FIG. 5B, system 100 can be configured such that reader device120 sends a request 302 in communication 301 to sensor control device102 for an identifier 304. Sensor control device 102 communicatesidentifier 304 to reader device 120 in communication 303. Token 402 isprovided to reader device 120 with the assistance of the user, e.g.,such as by scanning token 402 from packaging as depicted in FIG. 5A.This can occur prior to the sending of communication 301, concurrentlywith the sending of communications 301 or 303, or after the receipt ofcommunication 303 by reader device 120. Regardless, after token 402 isprovided to reader device 120, it is forward to trusted computer system180 in communication 406 and the authentication process continuesthrough completion as described with respect to FIG. 4.

In the embodiments of FIGS. 4 and 5A-B, registration database 181 withinthe remotely located trusted computer system 180 can be used to verifythat tokens 402 and identifiers 304 are authentic. The embodimentdescribed with respect to FIG. 4 can be modified such that the varioustokens 402 and identifiers 304 are stored within a local registrationdatabase (e.g., database 129) of reader device 120 in a manner similarto that described with respect to the trusted computer system'sregistration database 181 (see, e.g., FIG. 3D).

In such a configuration, reader device 120 would perform those tasksdescribed with respect to FIG. 4 as being performed by trusted computersystem 180 (e.g., retrieval of identifier 304 from the database andcomparison with the identifier 304 obtained from sensor control device102 to determine if they match, using identifier 304 as an index tolocate token 402 within the database, comparison of token 402 from thedatabase with the token 402 obtained from sensor control device 102 todetermine if they match, optionally generating an authentication result,etc.). There would no longer be a need to send communications 406 and408, and the need for an internet connection 142 would be obviated forpurposes of authenticating a particular sensor control device (althoughan internet connection may be desired for other reasons, such asproviding updates as to used identifiers and tokens to trusted computersystem 180, so that updates can be disseminated to other reader devicesand instances of unauthorized usage can be monitored, etc.).

In yet another embodiment, token 402 can be provided to reader device120 in a manner similar to that described with respect to FIGS. 4 and5A-B, but reader device 120 does not forward token 402 to trustedcomputer system 180. Instead, reader device sends only identifier 304 totrusted computer system 180, which can then retrieve the correspondingversion of token 402 stored within registration database and send thatretrieved version back to reader device 120 (with or withoutauthentication result 306). Reader device 120 can then determine whethertoken 402 provided by sensor control device 102 matches the token 402received from trusted computer system 180 and conclude whether or notsensor control device 102 is authentic.

A number of additional embodiments will now be described that make useof authentication techniques having multiple keys, such as asymmetric(public key) cryptography and/or symmetric cryptography. Theseembodiments can be used alone or with any of the other embodiments, suchas those using identifiers and/or tokens, described herein.

In public key cryptography, both a public key and a private key aretypically used. The private key can be associated with sensor controldevice 102 and the public key can be associated with reader device 120.For example, one of any number of key generation algorithms, which areknown in the art, can be used to generate a private key and acorresponding public key. Examples of key generation algorithms that canbe used include, but are not limited to RSA algorithms such as thosedescribed in the Public-Key Cryptography Standards (PKCS). Any desiredkey length can be used, but keys with longer lengths will typicallyprovide more security. For example, key lengths of 128 bits, 256 bits,512 bits, 1024 bits, 2048 bits, and 5096 bits, as well as others, can beused.

FIG. 6 depicts an example embodiment of system 100 utilizing both aprivate key 602 and a public key 604. Here, sensor control devicepackaging 501 has a barcode label 502 representing private key 602,which can be in an encrypted format. Optical scanner 505 of readerdevice 120 scans the barcode on label 502 and retrieves private key 602.

A public key 604 is stored within the memory of reader device 120. Afterreader device 120 obtains private key 602 and applies any requireddecryption algorithm to it, reader device 120 uses an algorithm storedthereon and public key 604 to algorithmically verify whether private key602 is an authentic key, in accordance with techniques that will bereadily apparent to those of ordinary skill in the art. If private key602 is verified as authentic, then reader device 120 can initiate orcontinue normal operation with sensor control device 102. Conversely, ifprivate key 602 is not verified as authentic, then it can be assumedthat sensor control device 102 is counterfeit or otherwise not suitablefor use, and reader device 120 ceases normal operation with sensorcontrol device 102. While private key 602 is shown and described here asbeing optically represented on packaging 501 in barcode format, itshould be noted that private key 602 can be associated with packaging501 in any of the manners described with respect to the embodiments ofFIGS. 5A-B. Also, private key 602 can be stored in the memory of sensorcontrol device 102 during, for instance, manufacturing, and obtained byreader device 120 by communication over wired or wireless path 140.

In additional embodiments, private key 602 can be kept with themanufacturer, for example, with trusted computer system 180, and publickey 604 can be stored in the memory of reader device 120 or sensorcontrol device 102. In some embodiments, private key 602 can be usedwith a signing algorithm to generate a digital signature (or todigitally sign data) that is stored within non-volatile memory of sensorcontrol device 102. Reader device 120 can be provided with this digitalsignature and can use public key 604 to algorithmically verify theauthenticity of the signature. In these embodiments, trusted computersystem 180 can act as a certificate authority (CA) or registrationauthority (RA) and can include a central directory as a repository forgenerated private keys, public keys, and/or digital signatures. Thecentral directory can be a database that is separate from registrationdatabase 181, or it can be the same database.

Any desired technique or scheme that relies on public and private keys(e.g., key generation algorithms, signing algorithms, and signatureverifying algorithms) can be used to implement the systems, devices, andmethods described herein. These include, but are not limited to,techniques or schemes based on the RSA algorithms (and their variants),El Gamal algorithms (and their variants), Digital Signature Algorithm(DSA) (described in U.S. Pat. No. 5,231,668, which is incorporated byreference herein for all purposes) (and its variants), and ellipticalcurve-based algorithms (and its variants), and Rabin algorithms (and itsvariants).

In some embodiments, the digital signatures can be used with or withindigital certificates (also referred to as public key certificates oridentity certificates), for example, to bind a public key stored withina reader device to the individual that uses the reader device. Thedigital certificates can include any combination of the following (orinformation representative of the following): a serial number thatuniquely identifies the digital signature, a subject (e.g., the useridentified), the signing algorithm used to create signature, the digitalsignature itself, and identification of the issuer of the certificate, adate from which the certificate is first valid, a date to which thecertificate is valid (e.g., an expiration date), a purpose of the publickey, the public key itself, a thumbprint algorithm (the algorithm usedto hash the certificate, if certificate is hashed), and the thumbprint(the hash itself, if used).

One such example embodiment using this approach is depicted in FIG. 7.Here, reader device 120 can optionally send a signature request 701 incommunication 702 to sensor control device 102. In response, sensorcontrol device 102 retrieves digital signature 703 from memory andcommunicates it to reader device 120 in communication 704. Reader device120 can then perform a verification of signature 703 using public key604, which is stored in the memory thereof. If the signature 703 isverified, reader device 120 can initiate or continue normal operationwith sensor control device 102. Conversely, if signature 703 isdetermined to not be authentic, e.g., signature 703 fails theverification process, then reader device 120 can cease operation withsensor control device 102 and inform the user of the same.

In some embodiments, calibration parameters are determined for eachsensor 104 during the manufacturing process and are stored innon-volatile memory of sensor control device 102. Some examples of theseparameters are described in US Publication 2010/0230285, which isincorporated by reference herein for this and all other purposes. Thesecalibration parameters can account for variations in the manufacturingprocess, and/or time-varying parameters (e.g., drift) of the sensor 104,and can be used to compensate for those variations and achieve accuratemeasurements of analyte levels. In some embodiments, digital signature703 can be obtained by using a signing algorithm on private key 602 andthe calibration parameters (e.g., the signed data) for that particularsensor control device 102. Digital signature 703 can be stored in thememory of sensor control device 102 along with a copy of thosecalibration parameters. Both digital signature 703 and the calibrationparameters can be read from sensor control device 102 with reader device120.

Reader device 120 can then apply a signature verifying algorithm toverify the authenticity of digital signature 703 and retrieve thecalibration parameters from signature 703. The retrieved, unsignedcalibration parameters can then be compared with those that were readdirectly from sensor control device 102 to see if they match. Becausecalibration parameters typically vary from sensor to sensor, a digitalsignature 703 that is copied from an authentic sensor control device 102and reproduced on a counterfeit sensor control device 102 would containcalibration parameters that would almost certainly not match the actualcalibration parameters stored within that sensor control device 102.Thus, counterfeiting would be deterred. Further, the calibrationparameters can play a significant role in achieving accurate analytemeasurements, and therefore a third-party would not be able to usecopied calibration parameters without significantly compromising theaccuracy of sensor control device 102. The matching of calibrationparameters can be treated as verification of the particular sensorcontrol device 102, and calibration parameters that differ can betreated as indicative of a counterfeit device 102.

FIGS. 8A-C are flow diagrams depicting an example embodiment of a method800 of using system 100. In this embodiment, each sensor control device102 has an identifier 304 associated with it that includes a serialnumber and a random number, where the random number is used to increasethe difficulty of predicting future values of authentic identifiers by athird party. Here, steps 802 through 810 can be performed by themanufacturer or distributor of system 100, or at least of sensor controldevice 102. In this example, both an identifier verification process anda key verification process are used, although it should be understoodthat either may be used by itself without the other.

It should be understood that, while FIGS. 8A-C are shown with stepsoccurring in a particular order, one of ordinary skill in the art willreadily recognize that it is not necessary that the steps be performedin the specific order shown, and that variations in the order ofperformance of the steps, including performing steps simultaneously orwith large periods of time in between, are within the scope of thepresent disclosure.

At 802, an identifier 304, which in this example is a serial number, isgenerated and assigned to the subject sensor control device 102. At 804,a random number is generated and assigned to the subject sensor controldevice 102. At 806, at least one key pair is generated, including both aprivate key 602 and a public key 604. In practice, a large number ofkeys may be generated during this step. At 808, private key 602 is usedwith the serial number and the random number to generate a digitalsignature 703, which is stored on the subject sensor control device 102at 809. It should be noted that calibration parameters specific tosensor control device 102 can be used instead of, or in addition to therandom number. Also, the serial number can be randomized to alleviatethe need for a separate random number. At 810, the serial number, randomnumber, key pair, and/or digital signature is logged, for example, byproviding it to registration database 181 where it can be used laterduring the identifier verification process. Upon completing themanufacturing or configuration of sensor control device 102, it isdirectly or indirectly distributed to a user.

FIG. 8B depicts a compilation of steps or actions performed with sensorcontrol device 102 and reader device 120, and thus would typically beperformed by the user. Steps 812-828 are steps that can (but notnecessarily) be performed in real-time, e.g., as the user isaffirmatively interacting with sensor control device 102 and readerdevice 120 to set them up for operation, while steps 830-836 can beperformed on a non-real-time basis, e.g., at a scheduled time when theuser is not otherwise interacting with the system. At 812, the subjectsensor control device 102 is activated by the user. This may occur in anumber of ways, e.g., by pressing a switch, by unsealing device 102 fromits packaging, by applying device 102 to the body, etc. At 814, readerdevice 120 establishes a connection with sensor control device 102 overcommunication path 140 (see, e.g., FIG. 1). While (or after)establishing the connection, at 816, reader device 120 is provided withdigital signature 703 by sensor control device 102. Then, at 818, readerdevice 120 uses public key 604, which was previously stored in thememory of reader device 120, or was previously retrieved from themanufacturer (e.g., over the internet from trusted computer system 180),in a signature verifying algorithm to reduce digital signature 703 andobtain the serial number and random number contained therein.

If it is desired to confer with trusted computer system 180 forauthentication purposes (e.g., an internet connection is available),then at 819 reader device 120 can transmit the serial number to trustedcomputer system 180, which can receive it at 820. Step 820 is depictedin FIG. 8C, which illustrates the steps that can be performed at or withtrusted computer system 180. Referring still to FIG. 8C, at 821, trustedcomputer system 180 checks the serial number against a compilation ofused serial numbers and a compilation of counterfeit serial numbers(which may be the same compilation) that is stored within registrationdatabase 181 to see if that serial number has been used already or isknown (or suspected) to be counterfeit.

At 822, trusted computer system 180 will transmit an authenticationresult to reader device 120 indicating whether or not that serial numberis valid, e.g., suitable for use or not counterfeit. If the serialnumber is valid, then at 823, trusted computer system 180 can updateregistration database 181 to indicate usage of that serial number. Ifthe serial number is not valid, then at 824 a system notification oralarm can be generated to notify the administrator of trusted computersystem 180 that a potential counterfeiting has occurred, so that theincident can be investigated accordingly. At 840, which may be acontinuous act, trusted computer system 180 can monitor transmissionsfrom other reader devices 120 in the field to determine if the validserial number is received from another source. If it is received, thenthat can be indicative of counterfeiting. At 842, trusted computersystem 180 can transmit, or broadcast, an update to the reader devices120 associated with the counterfeit sensor control device 102 to notifythem that such device is not (or no longer) valid.

Referring back to FIG. 8B, if it is desired not to confer with trustedcomputer system 180, e.g., no internet connection is available or if itis desired to avoid performing an internet transaction (such as to savetime), etc., then at 825 reader device 120 can check the serial numberagainst a local compilation of serial numbers that indicates whether theserial numbers are used or counterfeit (e.g., database 129). If theserial number is not already used, or not suspected to be counterfeit,then, at 826, reader device 120 can update the local compilation toindicate usage of that serial number.

If it is determined that the serial number is not valid, either throughreceipt of the authentication result from trusted computer system 180 orthrough a local determination at reader device 120, then, at 827 readerdevice 120 displays a message to the user indicating the same and ceasesoperation with the subject sensor control device 120. If it isdetermined that the serial number is valid, then, at 828 reader device120 continues with normal operation with sensor control device 102,including the collection and display of sensed analyte data from sensorcontrol device 102.

When an internet connection again becomes available, or at a scheduledor convenient time, at 830, the serial number can be uploaded toregistration database 181 so that it can be added to the compilation ofused serial numbers stored therein. Also, at 832, an updated list ofused serial numbers and/or suspected counterfeit serial numbers can bedownloaded from registration database 181 and stored locally on readerdevice 120. If it is later determined or suspected that the serialnumber of sensor control device 102 is a counterfeit, then trustedcomputer system 180 can send a notification or alarm to reader device120 indicating that the sensor control device is no longer authorizedfor use (e.g., 842 in FIG. 8C), which can be received by reader device120 at 834 (FIG. 8B). At 836, a notification that a counterfeit deviceis being used is displayed or otherwise communicated to the user. Anacknowledgment by the user that this notification has been read andunderstood may be required prior to terminating operation with thecounterfeit sensor control device 102.

It should be understood that, for all of the example embodimentsdescribed herein where communications are sent from reader device 120 totrusted computer system 180 over the internet for the purposes ofauthentication, those embodiments can be modified such that theauthentication information stored at trusted computer system 180 (e.g.,information stored within registration database 181) is instead storedwithin reader device 120, and reader device 120 can perform theauthentication processes itself. In these cases, reader device 120 canlater verify its determination as to the authenticity of sensor controldevice 102 by communication with trusted computer system 180, either byhaving trusted computer system 180 conduct its own verification, or bydownloading relatively more current authentication information fromtrusted computer system 180 and re-verifying the authenticity of sensorcontrol device 102. Likewise, for all of the example embodimentsdescribed herein where reader device 120 performs its own authenticationof sensor control device 102 without communication over the internet(e.g., by reference to a locally stored registration database), theseembodiments can be modified such that reader device 120 instead reliesupon trusted computer system 180 to perform the authentication of sensorcontrol device 102 by communicating the requisite authenticationinformation to trusted computer system 180 over the internet and byreceiving an authentication result from trusted computer system 180.

For each embodiment disclosed herein, software and other mechanisms canbe provided for logging and monitoring instances where theauthentication process results in a sensor control device not beingauthenticated, in order to identify similarities and/or patterns thatcan be indicative of localized, widespread, or systematic abuse. Forexample, repeated use of the same identifier in a particular region canbe indicative of counterfeiting within that region, in which case themanufacturer can take corrective steps. The logging and/or monitoringfunction can be performed by trusted computer system 180 (or anadministrator thereof), reader device 120, or another device or system.In addition to the region of sale or use, instances of unauthorizedusage can be correlated to the identifier, token, private or public key,identity of the user, identity of the distributor, identity of thehospital or medical professional, model number of the sensor controldevice or reader device, serial number of the sensor control device orreader device, network address (e.g., IP address) of the reader device,insurer, insurance account, any combination of two or more of theaforementioned types of information, and the like.

Sensor Configurations

Analytes that may be monitored with system 100 include, but are notlimited to, acetyl choline, amylase, bilirubin, cholesterol, chorionicgonadotropin, glycosylated hemoglobin (HbAlc), creatine kinase (e.g.,CK-MB), creatine, creatinine, DNA, fructosamine, glucose, glucosederivatives, glutamine, growth hormones, hormones, ketones, ketonebodies, lactate, peroxide, prostate-specific antigen, prothrombin, RNA,thyroid stimulating hormone, and troponin. The concentration of drugs,such as, for example, antibiotics (e.g., gentamicin, vancomycin, and thelike), digitoxin, digoxin, drugs of abuse, theophylline, and warfarin,may also be monitored. In embodiments that monitor more than oneanalyte, the analytes may be monitored at the same or different times.

Analyte sensor 104 may include an analyte-responsive enzyme to provide asensing element. Some analytes, such as oxygen, can be directlyelectrooxidized or electroreduced on sensor 104, and more specificallyat least on a working electrode (not shown) of a sensor 104. Otheranalytes, such as glucose and lactate, require the presence of at leastone electron transfer agent and/or at least one catalyst to facilitatethe electrooxidation or electroreduction of the analyte. Catalysts mayalso be used for those analytes, such as oxygen, that can be directlyelectrooxidized or electroreduced on the working electrode. For theseanalytes, each working electrode includes a sensing element proximate toor on a surface of a working electrode. In many embodiments, a sensingelement is formed near or on only a small portion of at least a workingelectrode.

Each sensing element includes one or more components constructed tofacilitate the electrochemical oxidation or reduction of the analyte.The sensing element may include, for example, a catalyst to catalyze areaction of the analyte and produce a response at the working electrode,an electron transfer agent to transfer electrons between the analyte andthe working electrode (or other component), or both.

A variety of different sensing element configurations may be used. Incertain embodiments, the sensing elements are deposited on theconductive material of a working electrode. The sensing elements mayextend beyond the conductive material of the working electrode. In somecases, the sensing elements may also extend over other electrodes, e.g.,over the counter electrode and/or reference electrode (orcounter/reference where provided). In other embodiments, the sensingelements are contained on the working electrode, such that the sensingelements do not extend beyond the conductive material of the workingelectrode. In some embodiments a working electrode is configured toinclude a plurality of spatially distinct sensing elements. Additionalinformation related to the use of spatially distinct sensing elementscan be found in U.S. Provisional Application No. 61/421,371, entitled“Analyte Sensors with Reduced Sensitivity Variation,” which was filed onDec. 9, 2010, and which is incorporated by reference herein in itsentirety and for all purposes.

The terms “working electrode”, “counter electrode”, “referenceelectrode” and “counter/reference electrode” are used herein to refer toconductive sensor components, including, e.g., conductive traces, whichare configured to function as a working electrode, counter electrode,reference electrode or a counter/reference electrode respectively. Forexample, a working electrode includes that portion of a conductivematerial, e.g., a conductive trace, which functions as a workingelectrode as described herein, e.g., that portion of a conductivematerial which is exposed to an environment containing the analyte oranalytes to be measured, and which, in some cases, has been modifiedwith one or more sensing elements as described herein. Similarly, areference electrode includes that portion of a conductive material,e.g., conductive trace, which function as a reference electrode asdescribed herein, e.g., that portion of a conductive material which isexposed to an environment containing the analyte or analytes to bemeasured, and which, in some cases, includes a secondary conductivelayer, e.g., a Ag/AgCl layer. A counter electrode includes that portionof a conductive material, e.g., conductive trace which is configured tofunction as a counter electrode as described herein, e.g., that portionof a conductive trace which is exposed to an environment containing theanalyte or analytes to be measured. As noted above, in some embodiments,a portion of a conductive material, e.g., conductive trace, may functionas either or both of a counter electrode and a reference electrode. Inaddition, “working electrodes”, “counter electrodes”, “referenceelectrodes” and “counter/reference electrodes” may include portions,e.g., conductive traces, electrical contacts, or areas or portionsthereof, which do not include sensing elements but which are used toelectrically connect the electrodes to other electrical components.

Sensing elements that are in direct contact with the working electrode,e.g., the working electrode trace, may contain an electron transferagent to transfer electrons directly or indirectly between the analyteand the working electrode, and/or a catalyst to facilitate a reaction ofthe analyte. For example, a glucose, lactate, or oxygen electrode may beformed having sensing elements which contain a catalyst, includingglucose oxidase, glucose dehydrogenase, lactate oxidase, or laccase,respectively, and an electron transfer agent that facilitates theelectrooxidation of the glucose, lactate, or oxygen, respectively.

In other embodiments the sensing elements are not deposited directly onthe working electrode, e.g., the working electrode trace. Instead, thesensing elements may be spaced apart from the working electrode trace,and separated from the working electrode trace, e.g., by a separationlayer. A separation layer may include one or more membranes or films ora physical distance. In addition to separating the working electrodetrace from the sensing elements, the separation layer may also act as amass transport limiting layer and/or an interferent eliminating layerand/or a biocompatible layer.

In certain embodiments which include more than one working electrode,one or more of the working electrodes may not have corresponding sensingelements, or may have sensing elements that do not contain one or morecomponents (e.g., an electron transfer agent and/or catalyst) needed toelectrolyze the analyte. Thus, the signal at this working electrode maycorrespond to background signal which may be removed from the analytesignal obtained from one or more other working electrodes that areassociated with fully-functional sensing elements by, for example,subtracting the signal.

In certain embodiments, the sensing elements include one or moreelectron transfer agents. Electron transfer agents that may be employedare electroreducible and electrooxidizable ions or molecules havingredox potentials that are a few hundred millivolts above or below theredox potential of the standard calomel electrode (SCE). The electrontransfer agent may be organic, organometallic, or inorganic. Examples oforganic redox species are quinones and species that in their oxidizedstate have quinoid structures, such as Nile blue and indophenol.Examples of organometallic redox species are metallocenes includingferrocene. Examples of inorganic redox species are hexacyanoferrate(III), ruthenium hexamine, etc. Additional examples include thosedescribed in U.S. Pat. Nos. 6,736,957, 7,501,053 and 7,754,093, thedisclosures of each of which are incorporated herein by reference intheir entirety.

In certain embodiments, electron transfer agents have structures orcharges which prevent or substantially reduce the diffusional loss ofthe electron transfer agent during the period of time that the sample isbeing analyzed. For example, electron transfer agents include but arenot limited to a redox species, e.g., bound to a polymer which can inturn be disposed on or near the working electrode. The bond between theredox species and the polymer may be covalent, coordinative, or ionic.Although any organic, organometallic or inorganic redox species may bebound to a polymer and used as an electron transfer agent, in certainembodiments the redox species is a transition metal compound or complex,e.g., osmium, ruthenium, iron, and cobalt compounds or complexes. Itwill be recognized that many redox species described for use with apolymeric component may also be used, without a polymeric component.

Embodiments of polymeric electron transfer agents may contain a redoxspecies covalently bound in a polymeric composition. An example of thistype of mediator is poly(vinylferrocene). Another type of electrontransfer agent contains an ionically-bound redox species. This type ofmediator may include a charged polymer coupled to an oppositely chargedredox species. Examples of this type of mediator include a negativelycharged polymer coupled to a positively charged redox species such as anosmium or ruthenium polypyridyl cation.

Another example of an ionically-bound mediator is a positively chargedpolymer including quaternized poly (4-vinyl pyridine) or poly(1-vinylimidazole) coupled to a negatively charged redox species such asferricyanide or ferrocyanide. In other embodiments, electron transferagents include a redox species coordinatively bound to a polymer. Forexample, the mediator may be formed by coordination of an osmium orcobalt 2,2′-bipyridyl complex to poly(1-vinyl imidazole) or poly(4-vinylpyridine).

Suitable electron transfer agents are osmium transition metal complexeswith one or more ligands, each ligand having a nitrogen-containingheterocycle such as 2,2′-bipyridine, 1,10-phenanthroline, 1-methyl,2-pyridyl biimidazole, or derivatives thereof. The electron transferagents may also have one or more ligands covalently bound in a polymer,each ligand having at least one nitrogen-containing heterocycle, such aspyridine, imidazole, or derivatives thereof. One example of an electrontransfer agent includes (a) a polymer or copolymer having pyridine orimidazole functional groups and (b) osmium cations complexed with twoligands, each ligand containing 2,2′-bipyridine, 1,10-phenanthroline, orderivatives thereof, the two ligands not necessarily being the same.Some derivatives of 2,2′-bipyridine for complexation with the osmiumcation include but are not limited to 4,4′-dimethyl-2,2′-bipyridine andmono-, di-, and polyalkoxy-2,2′-bipyridines, including4,4′-dimethoxy-2,2′-bipyridine. Derivatives of 1,10-phenanthroline forcomplexation with the osmium cation include but are not limited to4,7-dimethyl-1,10-phenanthroline and mono, di-, andpolyalkoxy-1,10-phenanthrolines, such as4,7-dimethoxy-1,10-phenanthroline. Polymers for complexation with theosmium cation include but are not limited to polymers and copolymers ofpoly(1-vinyl imidazole) (referred to as “PVI”) and poly(4-vinylpyridine) (referred to as “PVP”). Suitable copolymer substituents ofpoly(1-vinyl imidazole) include acrylonitrile, acrylamide, andsubstituted or quaternized N-vinyl imidazole, e.g., electron transferagents with osmium complexed to a polymer or copolymer of poly(l-vinylimidazole).

Embodiments may employ electron transfer agents having a redox potentialranging from about −200 mV to about +200 mV versus the standard calomelelectrode (SCE). The sensing elements may also include a catalyst whichis capable of catalyzing a reaction of the analyte. The catalyst mayalso, in some embodiments, act as an electron transfer agent. Oneexample of a suitable catalyst is an enzyme which catalyzes a reactionof the analyte. For example, a catalyst, including a glucose oxidase,glucose dehydrogenase (e.g., pyrroloquinoline quinone (PQQ), dependentglucose dehydrogenase, flavine adenine dinucleotide (FAD) dependentglucose dehydrogenase, or nicotinamide adenine dinucleotide (NAD)dependent glucose dehydrogenase), may be used when the analyte ofinterest is glucose. A lactate oxidase or lactate dehydrogenase may beused when the analyte of interest is lactate. Laccase may be used whenthe analyte of interest is oxygen or when oxygen is generated orconsumed in response to a reaction of the analyte.

In certain embodiments, a catalyst may be attached to a polymer, crosslinking the catalyst with another electron transfer agent, which, asdescribed above, may be polymeric. A second catalyst may also be used incertain embodiments. This second catalyst may be used to catalyze areaction of a product compound resulting from the catalyzed reaction ofthe analyte. The second catalyst may operate with an electron transferagent to electrolyze the product compound to generate a signal at theworking electrode. Alternatively, a second catalyst may be provided inan interferent-eliminating layer to catalyze reactions that removeinterferents.

In certain embodiments, the sensor works at a low oxidizing potential,e.g., a potential of about +40 mV vs. Ag/AgCl. These sensing elementsuse, for example, an osmium (Os)-based mediator constructed for lowpotential operation. Accordingly, in certain embodiments the sensingelements are redox active components that include: (1) osmium-basedmediator molecules that include (bidente) ligands, and (2) glucoseoxidase enzyme molecules. These two constituents are combined togetherin the sensing elements of the sensor.

A mass transport limiting layer (not shown), e.g., an analyte fluxmodulating layer, may be included with the sensor to act as adiffusion-limiting barrier to reduce the rate of mass transport of theanalyte, for example, glucose or lactate, into the region around theworking electrodes. The mass transport limiting layers are useful inlimiting the flux of an analyte to a working electrode in anelectrochemical sensor so that the sensor is linearly responsive over alarge range of analyte concentrations and is easily calibrated. Masstransport limiting layers may include polymers and may be biocompatible.A mass transport limiting layer may provide many functions, e.g.,biocompatibility and/or interferent-eliminating functions, etc. A masstransport limiting layer may be applied to an analyte sensor asdescribed herein via any of a variety of suitable methods, including,e.g., dip coating and slot die coating.

In certain embodiments, a mass transport limiting layer is a membranecomposed of crosslinked polymers containing heterocyclic nitrogengroups, such as polymers of polyvinylpyridine and polyvinylimidazole.Embodiments also include membranes that are made of a polyurethane, orpolyether urethane, or chemically related material, or membranes thatare made of silicone, and the like.

A membrane may be formed by crosslinking in situ a polymer, modifiedwith a zwitterionic moiety, a non-pyridine copolymer component, andoptionally another moiety that is either hydrophilic or hydrophobic,and/or has other desirable properties, in an alcohol-buffer solution.The modified polymer may be made from a precursor polymer containingheterocyclic nitrogen groups. For example, a precursor polymer may bepolyvinylpyridine or polyvinylimidazole. Optionally, hydrophilic orhydrophobic modifiers may be used to “fine-tune” the permeability of theresulting membrane to an analyte of interest. Optional hydrophilicmodifiers, such as poly (ethylene glycol), hydroxyl or polyhydroxylmodifiers, may be used to enhance the biocompatibility of the polymer orthe resulting membrane.

A membrane may be formed in situ by applying an alcohol-buffer solutionof a crosslinker and a modified polymer over the enzyme-containingsensing elements and allowing the solution to cure for about one to twodays or other appropriate time period. The crosslinker-polymer solutionmay be applied over the sensing elements by placing a droplet ordroplets of the membrane solution on the sensor, by dipping the sensorinto the membrane solution, by spraying the membrane solution on thesensor, and the like. Generally, the thickness of the membrane iscontrolled by the concentration of the membrane solution, by the numberof droplets of the membrane solution applied, by the number of times thesensor is dipped in the membrane solution, by the volume of membranesolution sprayed on the sensor, or by any combination of these factors.In order to coat the distal and side edges of the sensor, the membranematerial may have to be applied subsequent to singulation of the sensorprecursors. In some embodiments, the analyte sensor is dip-coatedfollowing singulation to apply one or more membranes. Alternatively, theanalyte sensor could be slot-die coated wherein each side of the analytesensor is coated separately. A membrane applied in the above manner mayhave any combination of the following functions: (1) mass transportlimitation, i.e., reduction of the flux of analyte that can reach thesensing elements, (2) biocompatibility enhancement, or (3) interferentreduction.

In some embodiments, a membrane composition for use as a mass transportlimiting layer may include one or more leveling agents, e.g.,polydimethylsiloxane (PDMS). Additional information with respect to theuse of leveling agents can be found, for example, in U.S. PatentApplication Publication No. 2010/0081905, the disclosure of which isincorporated by reference herein in its entirety.

In some instances, the membrane may form one or more bonds with thesensing elements. The term “bonds” is intended to cover any type of aninteraction between atoms or molecules that allows chemical compounds toform associations with each other, such as, but not limited to, covalentbonds, ionic bonds, dipole-dipole interactions, hydrogen bonds, Londondispersion forces, and the like. For example, in situ polymerization ofthe membrane can form crosslinks between the polymers of the membraneand the polymers in the sensing elements. In certain embodiments,crosslinking of the membrane to the sensing element facilitates areduction in the occurrence of delamination of the membrane from thesensor.

In many instances entities are described herein as being coupled toother entities. It should be understood that the terms “coupled” and“connected” (or any of their forms) are used interchangeably herein and,in both cases, are generic to the direct coupling of two entities(without any non-negligible (e.g., parasitic) intervening entities) andthe indirect coupling of two entities (with one or more non-negligibleintervening entities). Where entities are shown as being directlycoupled together, or described as coupled together without descriptionof any intervening entity, it should be understood that those entitiescan be indirectly coupled together as well unless the context clearlydictates otherwise.

While the embodiments are susceptible to various modifications andalternative forms, specific examples thereof have been shown in thedrawings and are herein described in detail. It should be understood,however, that these embodiments are not to be limited to the particularform disclosed, but to the contrary, these embodiments are to cover allmodifications, equivalents, and alternatives falling within the spiritof the disclosure. Furthermore, any features, functions, steps, orelements of the embodiments may be recited in or added to the claims, aswell as negative limitations that define the inventive scope of theclaims by features, functions, steps, or elements that are not withinthat scope.

What is claimed is:
 1. A method of authentication in an in vivo analytemonitoring system, the method comprising: retrieving a private key, by areader device, from product packaging comprising a readable or scannableelement representative of the private key, wherein the analytemonitoring system includes a sensor control device comprising a sensorand analyte monitoring circuitry, wherein the sensor is adapted to beinserted into the body of a user, and wherein the product packaging isexternal to the sensor control device; attempting to authenticate theprivate key using a public key stored within the reader device; if thereader device determines that the private key is authentic and if thesensor has been inserted into the body of the user, then: receiving,with the reader device, information indicative of an analyte level ofthe user from the sensor control device; and displaying the informationindicative of the analyte level on a display of the reader device; andif the reader device determines that the private key is not authentic,then preventing operation of the reader device with the sensor controldevice.
 2. The method of claim 1, further comprising, in response todetermining that the private key is not authentic, displaying a messageon the display of the reader device indicating that the sensor controldevice is not authorized for use.
 3. The method of claim 1, wherein thereadable or scannable element is a barcode, wherein retrieving theprivate key by the reader device comprises scanning the barcode on theproduct packaging with an optical scanner of the reader device, andwherein the barcode is representative of the private key.
 4. The methodof claim 3, wherein the barcode is a QR code.
 5. The method of claim 1,wherein the readable or scannable element is an radio frequencyidentification (RFID) label, wherein retrieving the private key by thereader device comprises scanning the product packaging with an nearfield communication (NFC) component of the reader device, and whereinthe RFID label is configured to provide information representative ofthe private key in response to an NFC scan.
 6. The method of claim 1,wherein the readable or scannable element comprises a printed indiciarepresentative of the private key, and wherein the method furthercomprises prompting the user to manually input the printed indiciarepresentative of the private key into the reader device.
 7. The methodof claim 1, wherein the reader device is a smart phone, a tablet, asmart glass, or a smart glasses.
 8. The method of claim 1, wherein theproduct packaging is a container for the sensor control device.
 9. Themethod of claim 1, wherein the product packaging is a container for aninserter configured to place the sensor control device on a user's bodysuch that at least a portion of the sensor is in contact with a bodyfluid of the user.
 10. The method of claim 1, further comprisingcommunicating, by the reader device, with the sensor control device overa local wireless communication path using a near field communication(NFC) protocol.
 11. The method of claim 1, further comprisingcommunicating, by the reader device, with the sensor control device overa local wireless communication path using a radio frequencyidentification (RFID) protocol.
 12. The method of claim 1, furthercomprising communicating, by the reader device, with the sensor controldevice over a wireless communication path according to a wirelesscommunication protocol.
 13. The method of claim 1, wherein the readerdevice comprises location determining hardware configured to determine acurrent location of the reader device, the method further comprising:determining a current location of the reader device; retrieving anidentifier from the product packaging; sending the current location ofthe reader device and the retrieved identifier to a trusted computersystem; and determining, by the trusted computer system, whether thereader device is authorized to operate with the sensor control device inthe current location.
 14. The method of claim 13, the method furthercomprising terminating operation between the reader device and thesensor control device in response to a determination that the readerdevice is not authorized to operate with the sensor control device inthe current location.
 15. The method of claim 14, further comprisingdisplaying a message on a display of the reader device indicating thatthe sensor control device is not authorized for use in the currentlocation.
 16. The method of claim 13, wherein the identifier comprises aserial number of the sensor control device.